| Going R, Loo J, Liu T-J and Wu M (2014), "Germanium Gate PhotoMOSFET Integrated to Silicon Photonics", IEEE Journal of Selected Topics in Quantum Electronics. Vol. 20(4), pp. 1-7. |
| Abstract: This paper presents a novel germanium gated NMOS phototransistor integrated on a silicon photonics platform on silicon-on-insulator (SOI) substrate. The phototransistor is fabricated with a modified NMOS process flow, with germanium which is recrystallized using rapid melt growth during the source/drain activation anneal step. The resulting device, with 1-μm channel length, and 8-μm channel width, demonstrates a responsivity of over 18 A/W at 1550 nm with 583 nW of incident light. By increasing the incident power to 912 μW, the device operates at 2.5 GHz. Miniaturization is expected to improve both responsivity and speed in future devices. |
BibTeX:
@article{going_germanium_2014,
author = {Going, R.W. and Loo, J. and Liu, T.-J.K. and Wu, M.C.},
title = {Germanium Gate PhotoMOSFET Integrated to Silicon Photonics},
journal = {IEEE Journal of Selected Topics in Quantum Electronics},
year = {2014},
volume = {20},
number = {4},
pages = {1--7},
doi = {10.1109/JSTQE.2013.2294470}
}
|
| Chan TK, Megens M, Yoo B-W, Wyras J, Chang-Hasnain CJ, Wu MC and Horsley DA (2013), "Optical beamsteering using an 8x8 MEMS phased array with closed-loop interferometric phase control", Optics Express., January, 2013. Vol. 21(3), pp. 2807. |
BibTeX:
@article{chan_optical_2013,
author = {Chan, Trevor K. and Megens, Mischa and Yoo, Byung-Wook and Wyras, John and Chang-Hasnain, Connie J. and Wu, Ming C. and Horsley, David A.},
title = {Optical beamsteering using an 8x8 MEMS phased array with closed-loop interferometric phase control},
journal = {Optics Express},
year = {2013},
volume = {21},
number = {3},
pages = {2807},
url = {http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-21-3-2807&id=248796},
doi = {10.1364/OE.21.002807}
}
|
| Going R, Kim M-K and Wu MC (2013), "Metal-optic cavity for a high efficiency sub-fF Germanium photodiode on a Silicon waveguide", Optics Express., September, 2013. Vol. 21(19), pp. 22429. |
BibTeX:
@article{going_metal-optic_2013,
author = {Going, Ryan and Kim, Myung-Ki and Wu, Ming C},
title = {Metal-optic cavity for a high efficiency sub-fF Germanium photodiode on a Silicon waveguide},
journal = {Optics Express},
year = {2013},
volume = {21},
number = {19},
pages = {22429},
url = {http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-21-19-22429&id=264589},
doi = {10.1364/OE.21.022429}
}
|
| Kim M-K, Li Z, Huang K, Going R, Wu MC and Choo H (2013), "Engineering of metal-clad optical nanocavity to optimize coupling with integrated waveguides", Optics Express., November, 2013. Vol. 21(22), pp. 25796. |
BibTeX:
@article{kim_engineering_2013,
author = {Kim, Myung-Ki and Li, Zheng and Huang, Kun and Going, Ryan and Wu, Ming C. and Choo, Hyuck},
title = {Engineering of metal-clad optical nanocavity to optimize coupling with integrated waveguides},
journal = {Optics Express},
year = {2013},
volume = {21},
number = {22},
pages = {25796},
url = {http://www.opticsinfobase.org/abstract.cfm?URI=oe-21-22-25796},
doi = {10.1364/OE.21.025796}
}
|
| Seok TJ, Jamshidi A, Eggleston M and Wu MC (2013), "Mass-producible and efficient optical antennas with CMOS-fabricated nanometer-scale gap", Optics Express., July, 2013. Vol. 21(14), pp. 16561. |
BibTeX:
@article{seok_mass-producible_2013,
author = {Seok, Tae Joon and Jamshidi, Arash and Eggleston, Michael and Wu, Ming C.},
title = {Mass-producible and efficient optical antennas with CMOS-fabricated nanometer-scale gap},
journal = {Optics Express},
year = {2013},
volume = {21},
number = {14},
pages = {16561},
url = {http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-21-14-16561&id=258481},
doi = {10.1364/OE.21.016561}
}
|
| Yoo B-W, Megens M, Chan T, Sun T, Yang W, Chang-Hasnain CJ, Horsley DA and Wu MC (2013), "Optical phased array using high contrast gratings for two dimensional beamforming and beamsteering", Optics Express., May, 2013. Vol. 21(10), pp. 12238-12248. |
| Abstract: We have developed a microelectromechanical system (MEMS) optical phased array incorporating a high-index-contrast subwavelength grating (HCG) for beamforming and beamsteering in a range of ± 1.26° × 1.26°. Our approach needs only a thin single-layer HCG made of silicon, considerably improving its speed thanks to the low mass, and is suitable for high optical power applications. The measured resonant frequency of HCG is 0.32 MHz. |
BibTeX:
@article{yoo_optical_2013,
author = {Yoo, Byung-Wook and Megens, Mischa and Chan, Trevor and Sun, Tianbo and Yang, Weijian and Chang-Hasnain, Connie J. and Horsley, David A. and Wu, Ming C.},
title = {Optical phased array using high contrast gratings for two dimensional beamforming and beamsteering},
journal = {Optics Express},
year = {2013},
volume = {21},
number = {10},
pages = {12238--12248},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-21-10-12238},
doi = {10.1364/OE.21.012238}
}
|
| Chan ML, Yoxall B, Park H, Kang Z, Izyumin I, Chou J, Megens MM, Wu MC, Boser BE and Horsley DA (2012), "Design and characterization of MEMS micromotor supported on low friction liquid bearing", Sensors and Actuators A: Physical., April, 2012. Vol. 177(0), pp. 1-9. |
| Abstract: This paper examines the performance of rotating microdevices incorporating a liquid bearing to couple a rotating element to a fixed substrate. Liquid bearing technology promises to significantly improve the durability and lifetime of micromechanical motors. Here, the fluid is confined between the rotor and stator using surface patterning of a hydrophobic layer. Magnetic actuation of 10 mm diameter silicon rotor is used to characterize the liquid bearing motor at rotation rates up to 1800 rpm. Bearings with fluid thickness from 20 to 200 μm are characterized. A minimum torque of 0.15 μN-m is required to initiate rotation. At rotation rates above 720 rpm, the rotor wobble is less than ±1 mrad and the bearing exhibits viscous friction with a drag coefficient of 1.2 × 10−3 μN-m/rpm. The drag performance of the disk-type liquid bearing using H2O as the fluid is approximately 15 times lower than that demonstrated in a micro-ball bearing supported rotor. |
BibTeX:
@article{chan_design_2012,
author = {Chan, Mei Lin and Yoxall, Brian and Park, Hyunkyu and Kang, Zhaoyi and Izyumin, Igor and Chou, Jeffrey and Megens, Mischa M. and Wu, Ming C. and Boser, Bernhard E. and Horsley, David A.},
title = {Design and characterization of MEMS micromotor supported on low friction liquid bearing},
journal = {Sensors and Actuators A: Physical},
year = {2012},
volume = {177},
number = {0},
pages = {1--9},
url = {http://www.sciencedirect.com/science/article/pii/S0924424711004687},
doi = {10.1016/j.sna.2011.08.003}
}
|
| Choi S, Jamshidi A, Seok TJ, Wu MC, Zohdi TI and Pisano AP (2012), "Fast, High-Throughput Creation of Size-Tunable Micro/Nanoparticle Clusters via Evaporative Self-Assembly in Picoliter-Scale Droplets of Particle Suspension", Langmuir., February, 2012. Vol. 28(6), pp. 3102-3111. |
| Abstract: We report a fast, high-throughput method to create size-tunable micro/nanoparticle clusters via evaporative assembly in picoliter-scale droplets of particle suspension. Mediated by gravity force and surface tension force of a contacting surface, picoliter-scale droplets of the suspension are generated from a nanofabricated printing head. Rapid evaporative self-assembly of the particles on a hydrophobic surface leads to fast clustering of micro/nanoparticles and forms particle clusters of tunable sizes and controlled spacing. The evaporating behavior of the droplet is observed in real-time, and the clustering characteristics of the particles are understood based on the physics of evaporative-assembly. With this method, multiplex printing of various particle clusters with accurate positioning and alignment are demonstrated. Also, size-unifomity of the cluster arrays is thoroughly analyzed by examining the metallic nanoparticle cluster-arrays based on surface-enhanced Raman spectroscopy (SERS). |
BibTeX:
@article{choi_fast_2012,
author = {Choi, Sun and Jamshidi, Arash and Seok, Tae Joon and Wu, Ming C. and Zohdi, Tarek I. and Pisano, Albert P.},
title = {Fast, High-Throughput Creation of Size-Tunable Micro/Nanoparticle Clusters via Evaporative Self-Assembly in Picoliter-Scale Droplets of Particle Suspension},
journal = {Langmuir},
year = {2012},
volume = {28},
number = {6},
pages = {3102--3111},
url = {http://dx.doi.org/10.1021/la204362s},
doi = {10.1021/la204362s}
}
|
| Choo H, Kim M-K, Staffaroni M, Seok TJ, Bokor J, Cabrini S, Schuck PJ, Wu MC and Yablonovitch E (2012), "Nanofocusing in a metal-insulator-metal gap plasmon waveguide with a three-dimensional linear taper", Nature Photonics. Vol. 6(12), pp. 838-844. |
| Abstract: The development of techniques for efficiently confining photons on the deep sub-wavelength spatial scale will revolutionize scientific research and engineering practices. The efficient coupling of light into extremely small nanofocusing devices has been a major challenge in on-chip nanophotonics because of the need to overcome various loss mechanisms and the on-chip nanofabrication challenges. Here, we demonstrate experimentally the achievement of highly efficient nanofocusing in an Au–SiO2–Au gap plasmon waveguide using a carefully engineered three-dimensional taper. The dimensions of the SiO2 layer, perpendicular to the direction of wave propagation, taper linearly below 100 nm. Our simulations suggest that the three-dimensional linear-tapering approach could focus 830 nm light into a 2 × 5 nm2 area with ≤3 dB loss and an intensity enhancement of 3.0 × 104. In a two-photon luminescence measurement, our device achieved an intensity enhancement of 400 within a 14 × 80 nm2 area, and a transmittance of 74 |
BibTeX:
@article{choo_nanofocusing_2012,
author = {Choo, Hyuck and Kim, Myung-Ki and Staffaroni, Matteo and Seok, Tae Joon and Bokor, Jeffrey and Cabrini, Stefano and Schuck, P. James and Wu, Ming C. and Yablonovitch, Eli},
title = {Nanofocusing in a metal-insulator-metal gap plasmon waveguide with a three-dimensional linear taper},
journal = {Nature Photonics},
year = {2012},
volume = {6},
number = {12},
pages = {838--844},
url = {http://www.nature.com/nphoton/journal/v6/n12/full/nphoton.2012.277.html},
doi = {10.1038/nphoton.2012.277}
}
|
| Chou J, Yu K and Wu M (2012), "Electrothermally Actuated Lens Scanner and Latching Brake for Free-Space Board-to-Board Optical Interconnects", Journal of Microelectromechanical Systems., October, 2012. Vol. 21(5), pp. 1107 -1116. |
| Abstract: The design, fabrication, and characterization of an electrothermally actuated lens scanner with bistable mechanical brakes, for the application of free-space board-to-board optical interconnects, are presented. An electrothermally actuated stepper motor is used to scan a 2.8-mm-diameter lens shuttle by a maximum of x00B1;170 x03BC;m ( x00B1;1.57 x00B0; scanning angle). Bistable mechanical brakes, toggled with U-shaped thermal actuators, will grip and hold the lens shuttle in place while dissipating zero power. The minimum frictional braking force and maximum actuator force are both measured to be 0.75 mN. A position sensing detector is used to accurately measure the dynamics of the stepper motor and lens system, from which we verify our analytical model. Long-term testing results and solutions are also presented. We demonstrate a robust 10-Gb/s optical link capable of maintaining connection despite a board tilting of 0.45 x00B0; while dissipating zero power. |
BibTeX:
@article{chou_electrothermally_2012,
author = {Chou, J.B. and Yu, Kyoungsik and Wu, M.C.},
title = {Electrothermally Actuated Lens Scanner and Latching Brake for Free-Space Board-to-Board Optical Interconnects},
journal = {Journal of Microelectromechanical Systems},
year = {2012},
volume = {21},
number = {5},
pages = {1107 --1116},
doi = {10.1109/JMEMS.2012.2203791}
}
|
| Huang H, Yue Y, Zhang L, Chase C, Parekh D, Sedgwick F, Wu MC, Chang-Hasnain CJ, Tur M and Willner AE (2012), "Analog Signal Transmission in a High-Contrast-Gratings-Based Hollow-Core-Waveguide", Journal of Lightwave Technology., December, 2012. Vol. 30(23), pp. 3640-3646. |
| Abstract: In this paper, the performance of an on-chip hollow-core-waveguide (HW) using high-contrast gratings (HCG) for analog signal transmission is analyzed numerically. Simulation results indicate that after propagating 100 m in a HCG-HW with optimally designed parameters, there is very little degradation of either third-order intermodulation distortion spur-free dynamic range (IM3 SFDR) or third-order harmonic distortion (THD) SFDR. Due to the chromatic dispersion of the HCG-HW, the highest second-order harmonic distortion (SHD) SFDR is limited to 107.3 dB Hz(1/2). In addition, textgreater100 dB.Hz(2/3) SFDR can be achieved over a radio frequency (RF) range of 80 GHz and an optical wavelength bandwidth of 50 nm after propagation 100 m through a HCG-HW. The parameter dependence of the waveguide performance is also investigated. With a +/- 20nm variation on all parameters, the propagation length in an HCG-HW is limited to similar to 6m in order to maintain an IM3 SFDR of textgreater100 dB Hz(2/3.) |
BibTeX:
@article{huang_analog_2012,
author = {Huang, H. and Yue, Y. and Zhang, L. and Chase, C. and Parekh, D. and Sedgwick, F. and Wu, M. C. and Chang-Hasnain, C. J. and Tur, M. and Willner, A. E.},
title = {Analog Signal Transmission in a High-Contrast-Gratings-Based Hollow-Core-Waveguide},
journal = {Journal of Lightwave Technology},
year = {2012},
volume = {30},
number = {23},
pages = {3640--3646},
note = {WOS:000312266100001},
doi = {10.1109/JLT.2012.2224844}
}
|
| Pauzauskie PJ, Jamshidi A, Zaug JM, Baker S, Han TY-J, Satcher JH and Wu MC (2012), "In Situ Raman Spectroscopy of COOH-Functionalized SWCNTs Trapped with Optoelectronic Tweezers", Advances in OptoElectronics., February, 2012. Vol. 2012 |
| Abstract: Optoelectronic tweezers (OETs) were used to trap and deposit aqueous dispersions of carboxylic-acid-functionalized single-walled carbon nanotube bundles. Dark-field video microscopy was used to visualize the dynamics of the bundles both with and without virtual electrodes, showing rapid accumulation of carbon nanotubes when optical virtual electrodes are actuated. Raman microscopy was used to probe SWCNT materials following deposition onto metallic fiducial markers as well as during trapping. The local carbon nanotube concentration was observed to increase rapidly during trapping by more than an order of magnitude in less than one second due to localized optical dielectrophoresis forces. This combination of enrichment and spectroscopy with a single laser spot suggests a broad range of applications in physical, chemical, and biological sciences. |
BibTeX:
@article{pauzauskie_situ_2012,
author = {Pauzauskie, Peter J. and Jamshidi, Arash and Zaug, Joseph M. and Baker, Sarah and Han, T. Y.-J. and Satcher, Joe H. and Wu, Ming C.},
title = {In Situ Raman Spectroscopy of COOH-Functionalized SWCNTs Trapped with Optoelectronic Tweezers},
journal = {Advances in OptoElectronics},
year = {2012},
volume = {2012},
url = {http://www.hindawi.com/journals/aoe/2012/869829/abs/},
doi = {10.1155/2012/869829}
}
|
| Rasras M, Chen Y, Tu K-Y, Earnshaw M, Pardo F, Cappuzzo M, Chen E, Gomez L, Klemens F, Keller B, Bolle C, Buhl L, Wyrwas J, Wu M, Peach R, Meredith S, Middleton C and DeSalvo R (2012), "Reconfigurable Linear Optical FM Discriminator", IEEE Photonics Technology Letters., October, 2012. Vol. 24(20), pp. 1856 -1859. |
| Abstract: We present a reconfigurable optical discriminator filter for frequency modulated microwave-photonics link applications. The filter is based on a simplified ring-assisted Mach-Zehnder interferometer configuration. It enables conversion of a highly linear frequency to amplitude modulation. Operations in a fixed bandwidth (BW) of 30 GHz and a tunable bandwidth from 10 to 30 GHz are achieved using third- and fifth-order filters. A balanced frequency discrimination architecture with electronically reconfigurable transfer characteristics is demonstrated. We measured a output-third order intercept point (OIP3) linearity improvement over that of a dual-output Mach-Zehnder. |
BibTeX:
@article{rasras_reconfigurable_2012,
author = {Rasras, M.S. and Chen, Y. and Tu, Kun-Yii and Earnshaw, M.P. and Pardo, F. and Cappuzzo, M.A. and Chen, E.Y. and Gomez, L.T. and Klemens, F. and Keller, B. and Bolle, C. and Buhl, L. and Wyrwas, J.M. and Wu, M.C. and Peach, R. and Meredith, S. and Middleton, C. and DeSalvo, R.},
title = {Reconfigurable Linear Optical FM Discriminator},
journal = {IEEE Photonics Technology Letters},
year = {2012},
volume = {24},
number = {20},
pages = {1856 --1859},
doi = {10.1109/LPT.2012.2217483}
}
|
| Takahashi T, Nichols P, Takei K, Ford AC, Jamshidi A, Wu MC, Ning CZ and Javey A (2012), "Contact printing of compositionally graded CdSx Se 1−x nanowire parallel arrays for tunable photodetectors", Nanotechnology., February, 2012. Vol. 23(4), pp. 045201. |
BibTeX:
@article{takahashi_contact_2012,
author = {Takahashi, Toshitake and Nichols, Patricia and Takei, Kuniharu and Ford, Alexandra C and Jamshidi, Arash and Wu, Ming C and Ning, C Z and Javey, Ali},
title = {Contact printing of compositionally graded CdSx Se 1−x nanowire parallel arrays for tunable photodetectors},
journal = {Nanotechnology},
year = {2012},
volume = {23},
number = {4},
pages = {045201},
url = {http://iopscience.iop.org/0957-4484/23/4/045201},
doi = {10.1088/0957-4484/23/4/045201}
}
|
| Wyrwas JM, Peach R, Meredith S, Middleton C, Rasras MS, Tu K-Y, Earnshaw MP, Pardo F, Cappuzzo MA, Chen EY, Gomez LT, Klemens F, Keller R, Bolle C, Zhang L, Buhl L, Wu MC, Chen Y and DeSalvo R (2012), "Linear phase-and-frequency-modulated photonic links using optical discriminators", Optics Express., November, 2012. Vol. 20(24), pp. 26292-26298. |
| Abstract: We report our experimental results for linear analog optical links that use phase or frequency modulation and optical discrimination. The discriminators are based on two architectures: a cascaded MZI FIR lattice filter and a ring assisted MZI (RAMZI) IIR filter. For both types of discriminators, we demonstrate textgreater 6 dB improvement in the link’s third-order output intercept point (OIP3) over a MZM link. We show that the links have low second-order distortion when using balanced detection. Using high optical power, we demonstrate an OIP3 of 39.2 dBm. We also demonstrate 4.3dB improvement in signal compression. |
BibTeX:
@article{wyrwas_linear_2012,
author = {Wyrwas, J. M. and Peach, R. and Meredith, S. and Middleton, C. and Rasras, M. S. and Tu, Kun-Yii and Earnshaw, M. P. and Pardo, F. and Cappuzzo, M. A. and Chen, E. Y. and Gomez, L. T. and Klemens, F. and Keller, R. and Bolle, C. and Zhang, L. and Buhl, L. and Wu, M. C. and Chen, Y.K. and DeSalvo, R.},
title = {Linear phase-and-frequency-modulated photonic links using optical discriminators},
journal = {Optics Express},
year = {2012},
volume = {20},
number = {24},
pages = {26292--26298},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-20-24-26292},
doi = {10.1364/OE.20.026292}
}
|
| Yang W, Ferrara J, Grutter K, Yeh A, Chase C, Yue Y, Willner AE, Wu MC and Chang-Hasnain CJ (2012), "Low loss hollow-core waveguide on a silicon substrate", Nanophotonics., July, 2012. Vol. 1(1), pp. 23-29. |
| Abstract: AbstractOptical-fiber-based, hollow-core waveguides (HCWs) have opened up many new applications in laser surgery, gas sensors, and non-linear optics. Chip-scale HCWs are desirable because they are compact, light-weight and can be integrated with other devices into systems-on-a-chip. However, their progress has been hindered by the lack of a low loss waveguide architecture. Here, a completely new waveguiding concept is demonstrated using two planar, parallel, silicon-on-insulator wafers with high-contrast subwavelength gratings to reflect light in-between. We report a record low optical loss of 0.37 dB/cm for a 9-μm waveguide, mode-matched to a single mode fiber. Two-dimensional light confinement is experimentally realized without sidewalls in the HCWs, which is promising for ultrafast sensing response with nearly instantaneous flow of gases or fluids. This unique waveguide geometry establishes an entirely new scheme for low-cost chip-scale sensor arrays and lab-on-a-chip applications. |
BibTeX:
@article{yang_low_2012,
author = {Yang, Weijian and Ferrara, James and Grutter, Karen and Yeh, Anthony and Chase, Chris and Yue, Yang and Willner, Alan E. and Wu, Ming C. and Chang-Hasnain, Connie J.},
title = {Low loss hollow-core waveguide on a silicon substrate},
journal = {Nanophotonics},
year = {2012},
volume = {1},
number = {1},
pages = {23--29},
url = {http://www.degruyter.com/view/j/nanoph.2012.1.issue-1/nanoph-2012-0003/nanoph-2012-0003.xml}
}
|
| Zheng M, Yu Z, Joon Seok T, Chen Y-Z, Kapadia R, Takei K, Aloni S, Ager JW, Wu M, Chueh Y-L and Javey A (2012), "High optical quality polycrystalline indium phosphide grown on metal substrates by metalorganic chemical vapor deposition", Journal of Applied Physics., June, 2012. Vol. 111(12), pp. 123112-123112-6. |
| Abstract: III–V semiconductor solar cells have demonstrated the highest power conversion efficiencies to date. However, the cost of III-V solar cells has historically been too high to be practical outside of specialty applications. This stems from the cost of raw materials, need for a lattice-matched substrate for single-crystal growth, and complex epitaxial growth processes. To address these challenges, here, we explore the direct non-epitaxial growth of thin poly-crystalline films of III-Vs on metal substrates by using metalorganic chemical vapor deposition. This method minimizes the amount of raw material used while utilizing a low cost substrate. Specifically, we focus on InP which is known to have a low surface recombination velocity of carriers, thereby, making it an ideal candidate for efficient poly-crystalline cells where surface/interface properties at the grain boundaries are critical. The grown InP films are 1-3 μm thick and are composed of micron-sized grains that generally extend from the surface to the Mo substrate. They exhibit similar photoluminescence peak widths and positions as single-crystalline InP, as well as excellent crystallinity as examined through TEM and XRD analyses. This work presents poly-InP as a promising absorber layer for future photovoltaics. |
BibTeX:
@article{zheng_high_2012,
author = {Zheng, Maxwell and Yu, Zhibin and Joon Seok, Tae and Chen, Yu-Ze and Kapadia, Rehan and Takei, Kuniharu and Aloni, Shaul and Ager, Joel W. and Wu, Ming and Chueh, Yu-Lun and Javey, Ali},
title = {High optical quality polycrystalline indium phosphide grown on metal substrates by metalorganic chemical vapor deposition},
journal = {Journal of Applied Physics},
year = {2012},
volume = {111},
number = {12},
pages = {123112--123112-6},
url = {http://jap.aip.org/resource/1/japiau/v111/i12/p123112_s1},
doi = {10.1063/1.4730442}
}
|
| Garcia M, Ohta A, Valley J, Banie L, Espineda S, Boscardin J, Lue T and Wu M (2011), "Optoelectronic tweezers for use to identify and retrieve viable, optimal quality non-motile human sperm for ICSI: feasibility and biosafety studies", Human Reproduction., July, 2011. Vol. 26, pp. I350-I351. |
BibTeX:
@article{garcia_optoelectronic_2011,
author = {Garcia, M. and Ohta, A. and Valley, J. and Banie, L. and Espineda, S. and Boscardin, J. and Lue, T. and Wu, M.},
title = {Optoelectronic tweezers for use to identify and retrieve viable, optimal quality non-motile human sperm for ICSI: feasibility and biosafety studies},
journal = {Human Reproduction},
year = {2011},
volume = {26},
pages = {I350--I351},
note = {WOS:000294450500894}
}
|
| Kim M-K, Lakhani AM and Wu MC (2011), "Efficient waveguide-coupling of metal-clad nanolaser cavities", Optics Express., November, 2011. Vol. 19(23), pp. 23504-23512. |
| Abstract: Many remarkable semiconductor-based nanolaser cavities using metal have been reported in past few years. However, the efficient coupling of these small cavities to waveguides still remains a large challenge. Here, we show highly efficient coupling of a semiconductor-based metal-clad nanolaser cavity operating in the fundamental dielectric cavity mode to a silicon-on-insulator waveguide. By engineering the effective refractive index and the field distribution of the cavity mode, a coupling efficiency as high as 78% can be achieved for a metal-clad nanolaser with a modal volume of 0.28 (λ/n)3 while maintaining a high optical quality factor of textgreater 600. |
BibTeX:
@article{kim_efficient_2011,
author = {Kim, Myung-Ki and Lakhani, Amit M. and Wu, Ming C.},
title = {Efficient waveguide-coupling of metal-clad nanolaser cavities},
journal = {Optics Express},
year = {2011},
volume = {19},
number = {23},
pages = {23504--23512},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-23-23504},
doi = {10.1364/OE.19.023504}
}
|
| Kita A, Sakurai Y, Myers DR, Rounsevell R, Huang JN, Seok TJ, Yu K, Wu MC, Fletcher DA and Lam WA (2011), "Microenvironmental Geometry Guides Platelet Adhesion and Spreading: A Quantitative Analysis at the Single Cell Level", PLoS ONE., October, 2011. Vol. 6(10), pp. e26437. |
| Abstract: To activate clot formation and maintain hemostasis, platelets adhere and spread onto sites of vascular injury. Although this process is well-characterized biochemically, how the physical and spatial cues in the microenvironment affect platelet adhesion and spreading remain unclear. In this study, we applied deep UV photolithography and protein micro/nanostamping to quantitatively investigate and characterize the spatial guidance of platelet spreading at the single cell level and with nanoscale resolution. Platelets adhered to and spread only onto micropatterned collagen or fibrinogen surfaces and followed the microenvironmental geometry with high fidelity and with single micron precision. Using micropatterned lines of different widths, we determined that platelets are able to conform to micropatterned stripes as thin as 0.6 µm and adopt a maximum aspect ratio of 19 on those protein patterns. Interestingly, platelets were also able to span and spread over non-patterned regions of up to 5 µm, a length consistent with that of maximally extended filopodia. This process appears to be mediated by platelet filopodia that are sensitive to spatial cues. Finally, we observed that microenvironmental geometry directly affects platelet biology, such as the spatial organization and distribution of the platelet actin cytoskeleton. Our data demonstrate that platelet spreading is a finely-tuned and spatially-guided process in which spatial cues directly influence the biological aspects of how clot formation is regulated. |
BibTeX:
@article{kita_microenvironmental_2011,
author = {Kita, Ashley and Sakurai, Yumiko and Myers, David R. and Rounsevell, Ross and Huang, James N. and Seok, Tae Joon and Yu, Kyoungsik and Wu, Ming C. and Fletcher, Daniel A. and Lam, Wilbur A.},
title = {Microenvironmental Geometry Guides Platelet Adhesion and Spreading: A Quantitative Analysis at the Single Cell Level},
journal = {PLoS ONE},
year = {2011},
volume = {6},
number = {10},
pages = {e26437},
url = {http://dx.doi.org/10.1371/journal.pone.0026437},
doi = {10.1371/journal.pone.0026437}
}
|
| Lakhani AM, Yu K and Wu MC (2011), "Lasing in subwavelength semiconductor nanopatches", Semiconductor Science and Technology., January, 2011. Vol. 26(1), pp. 014013. |
BibTeX:
@article{lakhani_lasing_2011,
author = {Lakhani, Amit M and Yu, Kyoungsik and Wu, Ming C},
title = {Lasing in subwavelength semiconductor nanopatches},
journal = {Semiconductor Science and Technology},
year = {2011},
volume = {26},
number = {1},
pages = {014013},
url = {http://iopscience.iop.org/0268-1242/26/1/014013/},
doi = {10.1088/0268-1242/26/1/014013}
}
|
| Lakhani AM, Kim M-k, Lau EK and Wu MC (2011), "Plasmonic crystal defect nanolaser", Optics Express. Vol. 19(19), pp. 18237-18245. |
| Abstract: Surface plasmons are widely interesting due to their ability to probe nanoscale dimensions. To create coherent plasmons, we demonstrate a nanolaser based on a plasmonic bandgap defect state inside a surface plasmonic crystal. A one-dimensional semiconductor-based plasmonic crystal is engineered to have stopbands in which surface plasmons are prohibited from travelling in the crystalline structure. We then confine surface plasmons using a three-hole defect in the periodic structure. Using conventional III-V semiconductors, we achieve lasing in mode volumes as small as Veff = 0.3(λ0/n)3 at λ0 = 1342 nm, which is 10 times smaller than similar modes in photonic crystals of the same size. This demonstration should pave the way for achieving engineered nanolasers with deep-subwavelength mode volumes and attractive nanophotonics integration capabilities while enabling the use of plasmonic crystals as an attractive platform for designing plasmons. |
BibTeX:
@article{lakhani_plasmonic_2011,
author = {Lakhani, Amit M. and Kim, Myung-ki and Lau, Erwin K. and Wu, Ming C.},
title = {Plasmonic crystal defect nanolaser},
journal = {Optics Express},
year = {2011},
volume = {19},
number = {19},
pages = {18237--18245},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-19-18237},
doi = {10.1364/OE.19.018237}
}
|
| Lee MH, Lim N, Ruebusch DJ, Jamshidi A, Kapadia R, Lee R, Seok TJ, Takei K, Cho KY, Fan Z, Jang H, Wu M, Cho G and Javey A (2011), "Roll-to-Roll Anodization and Etching of Aluminum Foils for High-Throughput Surface Nanotexturing", Nano Lett.. Vol. 11(8), pp. 3425-3430. |
| Abstract: A high-throughput process for nanotexturing of hard and soft surfaces based on the roll-to-roll anodization and etching of low-cost aluminum foils is presented. The process enables the precise control of surface topography, feature size, and shape over large areas thereby presenting a highly versatile platform for fabricating substrates with user-defined, functional performance. Specifically, the optical and surface wetting properties of the foil substrates were systematically characterized and tuned through the modulation of the surface texture. In addition, textured aluminum foils with pore and bowl surface features were used as zeptoliter reaction vessels for the well-controlled synthesis of inorganic, organic, and plasmonic nanomaterials, demonstrating yet another powerful potential use of the presented approach. A high-throughput process for nanotexturing of hard and soft surfaces based on the roll-to-roll anodization and etching of low-cost aluminum foils is presented. The process enables the precise control of surface topography, feature size, and shape over large areas thereby presenting a highly versatile platform for fabricating substrates with user-defined, functional performance. Specifically, the optical and surface wetting properties of the foil substrates were systematically characterized and tuned through the modulation of the surface texture. In addition, textured aluminum foils with pore and bowl surface features were used as zeptoliter reaction vessels for the well-controlled synthesis of inorganic, organic, and plasmonic nanomaterials, demonstrating yet another powerful potential use of the presented approach. |
BibTeX:
@article{lee_roll--roll_2011,
author = {Lee, Min Hyung and Lim, Namsoo and Ruebusch, Daniel J. and Jamshidi, Arash and Kapadia, Rehan and Lee, Rebecca and Seok, Tae Joon and Takei, Kuniharu and Cho, Kee Young and Fan, Zhiyoung and Jang, Hwanung and Wu, Ming and Cho, Gyoujin and Javey, Ali},
title = {Roll-to-Roll Anodization and Etching of Aluminum Foils for High-Throughput Surface Nanotexturing},
journal = {Nano Lett.},
year = {2011},
volume = {11},
number = {8},
pages = {3425--3430},
url = {http://dx.doi.org/10.1021/nl201862d},
doi = {10.1021/nl201862d}
}
|
| Pint CL, Takei K, Kapadia R, Zheng M, Ford AC, Zhang J, Jamshidi A, Bardhan R, Urban JJ, Wu M, Ager JW, Oye MM and Javey A (2011), "Rationally Designed, Three-Dimensional Carbon Nanotube Back-Contacts for Efficient Solar Devices", Advanced Energy Materials., November, 2011. Vol. 1(6), pp. 1040-1045. |
BibTeX:
@article{pint_rationally_2011,
author = {Pint, Cary L. and Takei, Kuniharu and Kapadia, Rehan and Zheng, Maxwell and Ford, Alexandra C. and Zhang, Junjun and Jamshidi, Arash and Bardhan, Rizia and Urban, Jeffrey J. and Wu, Ming and Ager, Joel W. and Oye, Michael M. and Javey, Ali},
title = {Rationally Designed, Three-Dimensional Carbon Nanotube Back-Contacts for Efficient Solar Devices},
journal = {Advanced Energy Materials},
year = {2011},
volume = {1},
number = {6},
pages = {1040--1045},
url = {http://onlinelibrary.wiley.com/doi/10.1002/aenm.201100436/abstract},
doi = {10.1002/aenm.201100436}
}
|
| Seok TJ, Jamshidi A, Kim M, Dhuey S, Lakhani A, Choo H, Schuck PJ, Cabrini S, Schwartzberg AM, Bokor J, Yablonovitch E and Wu MC (2011), "Radiation Engineering of Optical Antennas for Maximum Field Enhancement", Nano Letters., July, 2011. Vol. 11(7), pp. 2606-2610. |
| Abstract: Optical antennas have generated much interest in recent years due to their ability to focus optical energy beyond the diffraction limit, benefiting a broad range of applications such as sensitive photodetection, magnetic storage, and surface-enhanced Raman spectroscopy. To achieve the maximum field enhancement for an optical antenna, parameters such as the antenna dimensions, loading conditions, and coupling efficiency have been previously studied. Here, we present a framework, based on coupled-mode theory, to achieve maximum field enhancement in optical antennas through optimization of optical antennas’ radiation characteristics. We demonstrate that the optimum condition is achieved when the radiation quality factor (Qrad) of optical antennas is matched to their absorption quality factor (Qabs). We achieve this condition experimentally by fabricating the optical antennas on a dielectric (SiO2) coated ground plane (metal substrate) and controlling the antenna radiation through optimizing the dielectric thickness. The dielectric thickness at which the matching condition occurs is approximately half of the quarter-wavelength thickness, typically used to achieve constructive interference, and leads to ∼20% higher field enhancement relative to a quarter-wavelength thick dielectric layer. |
BibTeX:
@article{seok_radiation_2011,
author = {Seok, Tae Joon and Jamshidi, Arash and Kim, Myungki and Dhuey, Scott and Lakhani, Amit and Choo, Hyuck and Schuck, Peter James and Cabrini, Stefano and Schwartzberg, Adam M. and Bokor, Jeffrey and Yablonovitch, Eli and Wu, Ming C.},
title = {Radiation Engineering of Optical Antennas for Maximum Field Enhancement},
journal = {Nano Letters},
year = {2011},
volume = {11},
number = {7},
pages = {2606--2610},
url = {http://dx.doi.org/10.1021/nl2010862},
doi = {10.1021/nl2010862}
}
|
| Valley JK, NingPei S, Jamshidi A, Hsu H-Y and Wu MC (2011), "A unified platform for optoelectrowetting and optoelectronic tweezers", Lab on a Chip. Vol. 11(7), pp. 1292. |
BibTeX:
@article{valley_unified_2011,
author = {Valley, Justin K. and NingPei, Shao and Jamshidi, Arash and Hsu, Hsan-Yin and Wu, Ming C.},
title = {A unified platform for optoelectrowetting and optoelectronic tweezers},
journal = {Lab on a Chip},
year = {2011},
volume = {11},
number = {7},
pages = {1292},
url = {http://pubs.rsc.org/en/Content/ArticleLanding/2011/LC/c0lc00568a},
doi = {10.1039/c0lc00568a}
}
|
| Wu MC (2011), "Optoelectronic tweezers", Nat Photon., June, 2011. Vol. 5(6), pp. 322-324. |
BibTeX:
@article{wu_optoelectronic_2011,
author = {Wu, Ming C},
title = {Optoelectronic tweezers},
journal = {Nat Photon},
year = {2011},
volume = {5},
number = {6},
pages = {322--324},
url = {http://dx.doi.org/10.1038/nphoton.2011.98},
doi = {10.1038/nphoton.2011.98}
}
|
| Zhang X, Pint CL, Lee MH, Schubert BE, Jamshidi A, Takei K, Ko H, Gillies A, Bardhan R, Urban JJ, Wu M, Fearing R and Javey A (2011), "Optically- and Thermally-Responsive Programmable Materials Based on Carbon Nanotube-Hydrogel Polymer Composites", Nano Letters., August, 2011. Vol. 11(8), pp. 3239-3244. |
| Abstract: A simple approach is described to fabricate reversible, thermally- and optically responsive actuators utilizing composites of poly(N-isopropylacrylamide) (pNIPAM) loaded with single-walled carbon nanotubes. With nanotube loading at concentrations of 0.75 mg/mL, we demonstrate up to 5 times enhancement to the thermal response time of the nanotube-pNIPAM hydrogel actuators caused by the enhanced mass transport of water molecules. Additionally, we demonstrate the ability to obtain ultrafast near-infrared optical response in nanotube-pNIPAM hydrogels under laser excitation enabled by the strong absorption properties of nanotubes. The work opens the framework to design complex and programmable self-folding materials, such as cubes and flowers, with advanced built-in features, including tunable response time as determined by the nanotube loading. |
BibTeX:
@article{zhang_optically-_2011,
author = {Zhang, Xiaobo and Pint, Cary L. and Lee, Min Hyung and Schubert, Bryan Edward and Jamshidi, Arash and Takei, Kuniharu and Ko, Hyunhyub and Gillies, Andrew and Bardhan, Rizia and Urban, Jeffrey J. and Wu, Ming and Fearing, Ronald and Javey, Ali},
title = {Optically- and Thermally-Responsive Programmable Materials Based on Carbon Nanotube-Hydrogel Polymer Composites},
journal = {Nano Letters},
year = {2011},
volume = {11},
number = {8},
pages = {3239--3244},
url = {http://dx.doi.org/10.1021/nl201503e},
doi = {10.1021/nl201503e}
}
|
| Chueh Y-L, Fan Z, Takei K, Ko H, Kapadia R, Rathore AA, Miller N, Yu K, Wu M, Haller EE and Javey A (2010), "Black Ge Based on Crystalline/Amorphous Core/Shell Nanoneedle Arrays", Nano Lett.. Vol. 10(2), pp. 520-523. |
| Abstract: Direct growth of black Ge on low-temperature substrates, including plastics and rubber is reported. The material is based on highly dense, crystalline/amorphous core/shell Ge nanoneedle arrays with ultrasharp tips (?4 nm) enabled by the Ni catalyzed vapor?solid?solid growth process. Ge nanoneedle arrays exhibit remarkable optical properties. Specifically, minimal optical reflectance (textless1 is observed, even for high angles of incidence (?75°) and for relatively short nanoneedle lengths (?1 ?m). Furthermore, the material exhibits high optical absorption efficiency with an effective band gap of ?1 eV. The reported black Ge could potentially have important practical implications for efficient photovoltaic and photodetector applications on nonconventional substrates. Direct growth of black Ge on low-temperature substrates, including plastics and rubber is reported. The material is based on highly dense, crystalline/amorphous core/shell Ge nanoneedle arrays with ultrasharp tips (?4 nm) enabled by the Ni catalyzed vapor?solid?solid growth process. Ge nanoneedle arrays exhibit remarkable optical properties. Specifically, minimal optical reflectance (textless1 is observed, even for high angles of incidence (?75°) and for relatively short nanoneedle lengths (?1 ?m). Furthermore, the material exhibits high optical absorption efficiency with an effective band gap of ?1 eV. The reported black Ge could potentially have important practical implications for efficient photovoltaic and photodetector applications on nonconventional substrates. |
BibTeX:
@article{chueh_black_2010,
author = {Chueh, Yu-Lun and Fan, Zhiyong and Takei, Kuniharu and Ko, Hyunhyub and Kapadia, Rehan and Rathore, Asghar A. and Miller, Nate and Yu, Kyoungsik and Wu, Ming and Haller, E. E. and Javey, Ali},
title = {Black Ge Based on Crystalline/Amorphous Core/Shell Nanoneedle Arrays},
journal = {Nano Lett.},
year = {2010},
volume = {10},
number = {2},
pages = {520--523},
url = {http://dx.doi.org/10.1021/nl903366z},
doi = {10.1021/nl903366z}
}
|
| Ergen O, Ruebusch DJ, Fang H, Rathore AA, Kapadia R, Fan Z, Takei K, Jamshidi A, Wu M and Javey A (2010), "Shape-Controlled Synthesis of Single-Crystalline Nanopillar Arrays by Template-Assisted Vapor−Liquid−Solid Process", J. Am. Chem. Soc.. Vol. 132(40), pp. 13972-13974. |
| Abstract: Highly regular, single-crystalline nanopillar arrays with tunable shapes and geometry are synthesized by the template-assisted vapor?liquid?solid growth mechanism. In this approach, the grown nanopillars faithfully reproduce the shape of the pores because during the growth the liquid catalyst seeds fill the space available, thereby conforming to the pore geometry. The process is highly generic for various material systems, and as an example, CdS and Ge nanopillar arrays with square, rectangular, and circular cross sections are demonstrated. In the future, this technique can be used to engineer the intrinsic properties of NPLs as a function of three independently controlled dimensional parameters - length, width and height. Highly regular, single-crystalline nanopillar arrays with tunable shapes and geometry are synthesized by the template-assisted vapor?liquid?solid growth mechanism. In this approach, the grown nanopillars faithfully reproduce the shape of the pores because during the growth the liquid catalyst seeds fill the space available, thereby conforming to the pore geometry. The process is highly generic for various material systems, and as an example, CdS and Ge nanopillar arrays with square, rectangular, and circular cross sections are demonstrated. In the future, this technique can be used to engineer the intrinsic properties of NPLs as a function of three independently controlled dimensional parameters - length, width and height. |
BibTeX:
@article{ergen_shape-controlled_2010,
author = {Ergen, Onur and Ruebusch, Daniel J. and Fang, Hui and Rathore, Asghar A. and Kapadia, Rehan and Fan, Zhiyong and Takei, Kuniharu and Jamshidi, Arash and Wu, Ming and Javey, Ali},
title = {Shape-Controlled Synthesis of Single-Crystalline Nanopillar Arrays by Template-Assisted Vapor−Liquid−Solid Process},
journal = {J. Am. Chem. Soc.},
year = {2010},
volume = {132},
number = {40},
pages = {13972--13974},
url = {http://dx.doi.org/10.1021/ja1052413},
doi = {10.1021/ja1052413}
}
|
| Fan Z, Kapadia R, Leu PW, Zhang X, Chueh Y-L, Takei K, Yu K, Jamshidi A, Rathore AA, Ruebusch DJ, Wu M and Javey A (2010), "Ordered Arrays of Dual-Diameter Nanopillars for Maximized Optical Absorption", Nano Lett.. Vol. 10(10), pp. 3823-3827. |
| Abstract: Optical properties of highly ordered Ge nanopillar arrays are tuned through shape and geometry control to achieve the optimal absorption efficiency. Increasing the Ge materials filling ratio is shown to increase the reflectance while simultaneously decreasing the transmittance, with the absorbance showing a strong diameter dependency. To enhance the broad band optical absorption efficiency, a novel dual-diameter nanopillar structure is presented, with a small diameter tip for minimal reflectance and a large diameter base for maximal effective absorption coefficient. The enabled single-crystalline absorber material with a thickness of only 2 ?m exhibits an impressive absorbance of ?99% over wavelengths, ? = 300?900 nm. These results enable a viable and convenient route toward shape-controlled nanopillar-based high-performance photonic devices. Optical properties of highly ordered Ge nanopillar arrays are tuned through shape and geometry control to achieve the optimal absorption efficiency. Increasing the Ge materials filling ratio is shown to increase the reflectance while simultaneously decreasing the transmittance, with the absorbance showing a strong diameter dependency. To enhance the broad band optical absorption efficiency, a novel dual-diameter nanopillar structure is presented, with a small diameter tip for minimal reflectance and a large diameter base for maximal effective absorption coefficient. The enabled single-crystalline absorber material with a thickness of only 2 ?m exhibits an impressive absorbance of ?99% over wavelengths, ? = 300?900 nm. These results enable a viable and convenient route toward shape-controlled nanopillar-based high-performance photonic devices. |
BibTeX:
@article{fan_ordered_2010,
author = {Fan, Zhiyong and Kapadia, Rehan and Leu, Paul W. and Zhang, Xiaobo and Chueh, Yu-Lun and Takei, Kuniharu and Yu, Kyoungsik and Jamshidi, Arash and Rathore, Asghar A. and Ruebusch, Daniel J. and Wu, Ming and Javey, Ali},
title = {Ordered Arrays of Dual-Diameter Nanopillars for Maximized Optical Absorption},
journal = {Nano Lett.},
year = {2010},
volume = {10},
number = {10},
pages = {3823--3827},
url = {http://dx.doi.org/10.1021/nl1010788},
doi = {10.1021/nl1010788}
}
|
| Garcia MM, Ohta AT, Walsh TJ, Vittinghof E, Lin G, Wu MC and Lue TF (2010), "A Noninvasive, Motility Independent, Sperm Sorting Method and Technology to Identify and Retrieve Individual Viable Nonmotile Sperm for Intracytoplasmic Sperm Injection", The Journal of Urology., December, 2010. Vol. 184(6), pp. 2466-2472. |
| Abstract: Purpose For intracytoplasmic sperm injection in the absence of sperm motility it can be virtually impossible to distinguish viable from nonviable sperm. A reliable means to identify viable nonmotile sperm is needed and would likely improve the intracytoplasmic sperm injection success rate. Optoelectronic tweezers are a new technology that uses light induced dielectrophoresis fields to distinguish individual live cells from dead cells. We assessed the ability of optoelectronic tweezers to distinguish viable from nonviable individual nonmotile human sperm. Materials and Methods Fresh semen specimens from 6 healthy men were suspended in an isotonic sucrose/dextrose solution and incubated with 0.4% trypan blue dye (Sigma-Aldrich®). Within 15 minutes we randomly selected 5 motile and 50 nonmotile sperm, including 25 trypan negative, followed by 25 trypan positive sperm, under 200× magnification for optoelectronic tweezers assay. We recorded the individual sperm response (attraction or repulsion) to the optoelectronic tweezer field and trypan staining status. Results From each subject 55 unwashed sperm were individually assayed for a total of 330. All motile sperm were attracted to optoelectronic tweezers. Of 150 trypan negative (viable) sperm 132 (88 were attracted to the optoelectronic tweezer field with 0.88 sensitivity (95% CI 0.82–0.93) vs that of the trypan blue assay. All 150 trypan positive (nonviable) sperm were repulsed by or neutral to the optoelectronic tweezer field with 1.0 specificity (95% CI 0.98–1.00) vs that of the trypan blue assay. Type I error equaled 0 and overall assay agreement was 94 Conclusions The optoelectronic tweezer assay can distinguish viable from nonviable nonmotile viable sperm with sensitivity comparable to that of the trypan blue assay and equal specificity. Optoelectronic tweezers are a promising means of selecting sperm for intracytoplasmic sperm injection. |
BibTeX:
@article{garcia_noninvasive_2010,
author = {Garcia, Maurice M. and Ohta, Aaron T. and Walsh, Thomas J. and Vittinghof, Eric and Lin, Guiting and Wu, Ming C. and Lue, Tom F.},
title = {A Noninvasive, Motility Independent, Sperm Sorting Method and Technology to Identify and Retrieve Individual Viable Nonmotile Sperm for Intracytoplasmic Sperm Injection},
journal = {The Journal of Urology},
year = {2010},
volume = {184},
number = {6},
pages = {2466--2472},
url = {http://www.sciencedirect.com/science/article/pii/S0022534710042795},
doi = {10.1016/j.juro.2010.08.026}
}
|
| Hsu H-y, Ohta AT, Chiou P-Y, Jamshidi A, Neale SL and Wu MC (2010), "Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in cell culture media", Lab on a Chip. Vol. 10(2), pp. 165. |
BibTeX:
@article{hsu_phototransistor-based_2010,
author = {Hsu, Hsan-yin and Ohta, Aaron T. and Chiou, Pei-Yu and Jamshidi, Arash and Neale, Steven L. and Wu, Ming C.},
title = {Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in cell culture media},
journal = {Lab on a Chip},
year = {2010},
volume = {10},
number = {2},
pages = {165},
url = {http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=LC&Year=2009&ManuscriptID=b906593h&Iss=Advance_Article},
doi = {10.1039/b906593h}
}
|
| Ohta AT, Garcia M, Valley JK, Banie L, Hsu H-Y, Jamshidi A, Neale SL, Lue T and Wu MC (2010), "Motile and non-motile sperm diagnostic manipulation using optoelectronic tweezers", Lab on a Chip. Vol. 10(23), pp. 3213. |
BibTeX:
@article{ohta_motile_2010,
author = {Ohta, Aaron T. and Garcia, Maurice and Valley, Justin K. and Banie, Lia and Hsu, Hsan-Yin and Jamshidi, Arash and Neale, Steven L. and Lue, Tom and Wu, Ming C.},
title = {Motile and non-motile sperm diagnostic manipulation using optoelectronic tweezers},
journal = {Lab on a Chip},
year = {2010},
volume = {10},
number = {23},
pages = {3213},
url = {http://pubs.rsc.org/en/Content/ArticleLanding/2010/LC/c0lc00072h},
doi = {10.1039/c0lc00072h}
}
|
| Valley JK, Swinton P, Boscardin WJ, Lue TF, Rinaudo PF, Wu MC and Garcia MM (2010), "Preimplantation Mouse Embryo Selection Guided by Light-Induced Dielectrophoresis", PLoS ONE., April, 2010. Vol. 5(4), pp. e10160. |
| Abstract: Selection of optimal quality embryos for in vitro fertilization (IVF) transfer is critical to successful live birth outcomes. Currently, embryos are chosen based on subjective assessment of morphologic developmental maturity. A non-invasive means to quantitatively measure an embryo's developmental maturity would reduce the variability introduced by the current standard. We present a method that exploits the scaling electrical properties of pre-transfer embryos to quantitatively discern embryo developmental maturity using light-induced dielectrophoresis (DEP). We show that an embryo's DEP response is highly correlated with its developmental stage. Uniquely, this technique allows one to select, in sequence and under blinded conditions, the most developmentally mature embryos among a mixed cohort of morphologically indistinguishable embryos cultured in optimized and sub-optimal culture media. Following assay, embryos continue to develop normally in vitro. Light-induced dielectrophoresis provides a non-invasive, quantitative, and reproducible means to select embryos for applications including IVF transfer and embryonic stem cell harvest. |
BibTeX:
@article{valley_preimplantation_2010,
author = {Valley, Justin K. and Swinton, Paul and Boscardin, W. John and Lue, Tom F. and Rinaudo, Paolo F. and Wu, Ming C. and Garcia, Maurice M.},
title = {Preimplantation Mouse Embryo Selection Guided by Light-Induced Dielectrophoresis},
journal = {PLoS ONE},
year = {2010},
volume = {5},
number = {4},
pages = {e10160},
url = {http://dx.doi.org/10.1371/journal.pone.0010160},
doi = {10.1371/journal.pone.0010160}
}
|
| Yu K, Lakhani A and Wu MC (2010), "Subwavelength metal-optic semiconductor nanopatch lasers", Optics Express., April, 2010. Vol. 18(9), pp. 8790-8799. |
| Abstract: We report on near infrared semiconductor nanopatch lasers with subwavelength-scale physical dimensions (0.019 cubic wavelengths) and effective mode volumes (0.0017 cubic wavelengths). We observe lasing in the two most fundamental optical modes which resemble oscillating electrical and magnetic dipoles. The ultra-small laser volume is achieved with the presence of nanoscale metal patches which suppress electromagnetic radiation into free-space and convert a leaky cavity into a highly-confined subwavelength optical resonator. Such ultra-small lasers with metallodielectric cavities will enable broad applications in data storage, biological sensing, and on-chip optical communication. |
BibTeX:
@article{yu_subwavelength_2010,
author = {Yu, Kyoungsik and Lakhani, Amit and Wu, Ming C.},
title = {Subwavelength metal-optic semiconductor nanopatch lasers},
journal = {Optics Express},
year = {2010},
volume = {18},
number = {9},
pages = {8790--8799},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-18-9-8790},
doi = {10.1364/OE.18.008790}
}
|
| Chou J, Yu K, Horsley D, Yoxall B, Mathai S, Tan MRT, Wang SY and Wu MC (2009), "Robust free space board-to-board optical interconnect with closed loop MEMS tracking", Applied Physics A: Materials Science & Processing. Vol. 95(4), pp. 973-982. |
BibTeX:
@article{chou_robust_2009,
author = {Chou, J. and Yu, K. and Horsley, D. and Yoxall, B. and Mathai, S. and Tan, M. R. T. and Wang, S. Y. and Wu, M. C.},
title = {Robust free space board-to-board optical interconnect with closed loop MEMS tracking},
journal = {Applied Physics A: Materials Science & Processing},
year = {2009},
volume = {95},
number = {4},
pages = {973--982}
}
|
| Fan Z, Razavi H, Do J, Moriwaki A, Ergen O, Chueh YL, Leu PW, Ho JC, Takahashi T and Reichertz LA (2009), "Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates", Nature Materials. |
BibTeX:
@article{fan_three-dimensional_2009,
author = {Fan, Z. and Razavi, H. and Do, J. and Moriwaki, A. and Ergen, O. and Chueh, Y. L. and Leu, P. W. and Ho, J. C. and Takahashi, T. and Reichertz, L. A.},
title = {Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates},
journal = {Nature Materials},
year = {2009}
}
|
| Jamshidi A, Neale SL, Yu K, Pauzauskie PJ, Schuck PJ, Valley JK, Hsu H-Y, Ohta AT and Wu MC (2009), "NanoPen: Dynamic, Low-Power, and Light-Actuated Patterning of Nanoparticles", Nano Letters., August, 2009. Vol. 9(8), pp. 2921-2925. |
BibTeX:
@article{jamshidi_nanopen:_2009,
author = {Jamshidi, Arash and Neale, Steven L. and Yu, Kyoungsik and Pauzauskie, Peter J. and Schuck, Peter James and Valley, Justin K. and Hsu, Hsan-Yin and Ohta, Aaron T. and Wu, Ming C.},
title = {NanoPen: Dynamic, Low-Power, and Light-Actuated Patterning of Nanoparticles},
journal = {Nano Letters},
year = {2009},
volume = {9},
number = {8},
pages = {2921--2925},
url = {http://pubs.acs.org/doi/abs/10.1021/nl901239a},
doi = {10.1021/nl901239a}
}
|
| Lau ANK, Ohta AT, Phan HL, Hsu HY, Jamshidi A, Chiou PY and Wu MC (2009), "Antifouling coatings for optoelectronic tweezers", Lab on a Chip. Vol. 9(20), pp. 2952-2957. |
BibTeX:
@article{lau_antifouling_2009,
author = {Lau, A. N. K. and Ohta, A. T. and Phan, H. L. and Hsu, H. Y. and Jamshidi, A. and Chiou, P. Y. and Wu, M. C.},
title = {Antifouling coatings for optoelectronic tweezers},
journal = {Lab on a Chip},
year = {2009},
volume = {9},
number = {20},
pages = {2952--2957}
}
|
| Lau E, Wong LJ and Wu M (2009), "Enhanced Modulation Characteristics of Optical Injection-Locked Lasers: A Tutorial", Selected Topics in Quantum Electronics, IEEE Journal of. Vol. 15(3), pp. 618-633. |
BibTeX:
@article{lau_enhanced_2009,
author = {Lau, E.K. and Wong, Liang Jie and Wu, M.C.},
title = {Enhanced Modulation Characteristics of Optical Injection-Locked Lasers: A Tutorial},
journal = {Selected Topics in Quantum Electronics, IEEE Journal of},
year = {2009},
volume = {15},
number = {3},
pages = {618--633}
}
|
| Lau EK, Lakhani A, Tucker RS and Wu MC (2009), "Enhanced modulation bandwidth of nanocavity light emitting devices", Optics Express. Vol. 17(10), pp. 7790-7799. |
BibTeX:
@article{lau_enhanced_2009-1,
author = {Lau, E. K. and Lakhani, A. and Tucker, R. S. and Wu, M. C.},
title = {Enhanced modulation bandwidth of nanocavity light emitting devices},
journal = {Optics Express},
year = {2009},
volume = {17},
number = {10},
pages = {7790--7799}
}
|
| Neale SL, Ohta AT, Hsu HY, Valley JK, Jamshidi A and Wu MC (2009), "Trap profiles of projector based optoelectronic tweezers (OET) with HeLa cells", Optics express. Vol. 17(7), pp. 5231-5239. |
BibTeX:
@article{neale_trap_2009,
author = {Neale, S. L. and Ohta, A. T. and Hsu, H. Y. and Valley, J. K. and Jamshidi, A. and Wu, M. C.},
title = {Trap profiles of projector based optoelectronic tweezers (OET) with HeLa cells},
journal = {Optics express},
year = {2009},
volume = {17},
number = {7},
pages = {5231--5239}
}
|
| Pauzauskie PJ, Jamshidi A, Valley JK, Satcher Jr JH and Wu MC (2009), "Parallel trapping of multiwalled carbon nanotubes with optoelectronic tweezers", Applied Physics Letters. Vol. 95, pp. 113104. |
BibTeX:
@article{pauzauskie_parallel_2009,
author = {Pauzauskie, P. J. and Jamshidi, A. and Valley, J. K. and Satcher Jr, J. H. and Wu, M. C.},
title = {Parallel trapping of multiwalled carbon nanotubes with optoelectronic tweezers},
journal = {Applied Physics Letters},
year = {2009},
volume = {95},
pages = {113104}
}
|
| Shah GJ, Ohta AT, Chiou EPY, Wu MC and Kim C (2009), "EWOD-driven droplet microfluidic device integrated with optoelectronic tweezers as an automated platform for cellular isolation and analysis", Lab on a Chip. Vol. 9(12), pp. 1732-1739. |
BibTeX:
@article{shah_ewod-driven_2009,
author = {Shah, G. J. and Ohta, A. T. and Chiou, E. P. Y. and Wu, M. C. and Kim, CJCJ},
title = {EWOD-driven droplet microfluidic device integrated with optoelectronic tweezers as an automated platform for cellular isolation and analysis},
journal = {Lab on a Chip},
year = {2009},
volume = {9},
number = {12},
pages = {1732--1739}
}
|
| Sung H-K, Zhao X, Lau E, Parekh D, Chang-Hasnain C and Wu M (2009), "Optoelectronic Oscillators Using Direct-Modulated Semiconductor Lasers Under Strong Optical Injection", Selected Topics in Quantum Electronics, IEEE Journal of. Vol. 15(3), pp. 572-577. |
BibTeX:
@article{sung_optoelectronic_2009,
author = {Sung, Hyuk-Kee and Zhao, Xiaoxue and Lau, E.K. and Parekh, D. and Chang-Hasnain, C.J. and Wu, M.C.},
title = {Optoelectronic Oscillators Using Direct-Modulated Semiconductor Lasers Under Strong Optical Injection},
journal = {Selected Topics in Quantum Electronics, IEEE Journal of},
year = {2009},
volume = {15},
number = {3},
pages = {572--577}
}
|
| Tien MC, Ohta AT, Yu K, Neale SL and Wu MC (2009), "Heterogeneous integration of InGaAsP microdisk laser on a silicon platform using optofluidic assembly", Applied Physics A: Materials Science & Processing. Vol. 95(4), pp. 967-972. |
BibTeX:
@article{tien_heterogeneous_2009,
author = {Tien, M. C. and Ohta, A. T. and Yu, K. and Neale, S. L. and Wu, M. C.},
title = {Heterogeneous integration of InGaAsP microdisk laser on a silicon platform using optofluidic assembly},
journal = {Applied Physics A: Materials Science & Processing},
year = {2009},
volume = {95},
number = {4},
pages = {967--972}
}
|
| Tsai J, Hsieh T, Liao C, Chiou S, Hah D and Wu MC (2009), "Experimental characterization of two-axis MEMS scanners", Journal of Micromechanics and Microengineering. Vol. 19, pp. 045002. |
BibTeX:
@article{tsai_experimental_2009,
author = {Tsai, J. and Hsieh, T. and Liao, C. and Chiou, S. and Hah, D. and Wu, M. C.},
title = {Experimental characterization of two-axis MEMS scanners},
journal = {Journal of Micromechanics and Microengineering},
year = {2009},
volume = {19},
pages = {045002}
}
|
| Valley J, Ohta A, Hsu H-Y, Neale S, Jamshidi A and Wu M (2009), "Optoelectronic Tweezers as a Tool for Parallel Single-Cell Manipulation and Stimulation", Biomedical Circuits and Systems, IEEE Transactions on. Vol. 3(6), pp. 424-431. |
BibTeX:
@article{valley_optoelectronic_2009,
author = {Valley, J.K. and Ohta, A.T. and Hsan-Yin Hsu and Neale, S.L. and Jamshidi, A. and Wu, M.C.},
title = {Optoelectronic Tweezers as a Tool for Parallel Single-Cell Manipulation and Stimulation},
journal = {Biomedical Circuits and Systems, IEEE Transactions on},
year = {2009},
volume = {3},
number = {6},
pages = {424--431}
}
|
| Valley JK, Neale S, Hsu H-Y, Ohta AT, Jamshidi A and Wu MC (2009), "Parallel single-cell light-induced electroporation and dielectrophoretic manipulation", Lab on a Chip. Vol. 9(12), pp. 1714-1720. |
| Abstract: Electroporation is a common technique for the introduction of exogenous molecules across the, otherwise, impermeant cell membrane. Conventional techniques are limited by either low throughput or limited selectivity. Here we present a novel technique whereby we use patterned light to create virtual electrodes which can induce the parallel electroporation of single cells. This technique seamlessly integrates with optoelectronic tweezers to provide a single cell manipulation platform as well. We present evidence of parallel, single cell electroporation using this method through use of fluorescent dyes and dielectrophoretic responses. Additionally, through the use of integrated microfluidic channels, we show that cells remain viable following treatment in the device. Finally, we determine the optimal field dosage to inject propidium iodide into a HeLa cell and maintain cellular viability. |
BibTeX:
@article{valley_parallel_2009,
author = {Valley, Justin K. and Neale, Steven and Hsu, Hsan-Yin and Ohta, Aaron T. and Jamshidi, Arash and Wu, Ming C.},
title = {Parallel single-cell light-induced electroporation and dielectrophoretic manipulation},
journal = {Lab on a Chip},
year = {2009},
volume = {9},
number = {12},
pages = {1714--1720},
url = {http://dx.doi.org/10.1039/b821678a}
}
|
| Wyrwas JM and Wu MC (2009), "Dynamic Range of Frequency Modulated Direct-Detection Analog Fiber Optic Links", Lightwave Technology, Journal of. Vol. 27(24), pp. 5552-5562. |
BibTeX:
@article{wyrwas_dynamic_2009,
author = {Wyrwas, J. M. and Wu, M. C.},
title = {Dynamic Range of Frequency Modulated Direct-Detection Analog Fiber Optic Links},
journal = {Lightwave Technology, Journal of},
year = {2009},
volume = {27},
number = {24},
pages = {5552--5562}
}
|
| Yao J and Wu MC (2009), "Bandwidth-tunable add-drop filters based on micro-electro-mechanical-system actuated silicon microtoroidal resonators", Optics Letters. Vol. 34(17), pp. 2557-2559. |
BibTeX:
@article{yao_bandwidth-tunable_2009,
author = {Yao, J. and Wu, M. C.},
title = {Bandwidth-tunable add-drop filters based on micro-electro-mechanical-system actuated silicon microtoroidal resonators},
journal = {Optics Letters},
year = {2009},
volume = {34},
number = {17},
pages = {2557--2559}
}
|
| Chiou PY, Park S-Y and Wu MC (2008), "Continuous optoelectrowetting for picoliter droplet manipulation", Applied Physics Letters. Vol. 93(22), pp. 221110. |
BibTeX:
@article{chiou_continuous_2008,
author = {Chiou, P. Y. and Park, Sung-Yong and Wu, Ming C.},
title = {Continuous optoelectrowetting for picoliter droplet manipulation},
journal = {Applied Physics Letters},
year = {2008},
volume = {93},
number = {22},
pages = {221110},
url = {file://C:Documents and SettingsWU-PCMy DocumentsMy PublicationsNew Publications.DataChiou - COEW APL 2008-0414285058/Chiou - COEW APL 2008.pdf}
}
|
| Chiou P-Y, Chang Z and Wu MC (2008), "Droplet Manipulation With Light on Optoelectrowetting Device", Journal of Microelectromechanical Systems., February, 2008. Vol. 17(1), pp. 133-138. |
| Abstract: We have demonstrated a 2D droplet manipulation platform allowing fully optical manipulation of droplets on a photosensitive surface. Optically controlled injection, transport, separation, and multiple droplet manipulation have been achieved for nanoliter-size droplets. These functions are realized by sandwiching the droplets between two optoelectrowetting (OEW) surfaces. Optical illumination on OEW surfaces changes the surface wettability locally through the electrowetting mechanism. Optical illumination turns the initially Teflon-coated surface from hydrophobic to hydrophilic. This process is reversible and can be controlled in real time. We have achieved a maximum transport speed of 78 mm/s for a 100-nL droplet using a scanning laser beam. We have also demonstrated a fully decoupled 2D multidroplet manipulation on the OEW surfaces. Potentially, the OEW mechanism can be scaled up to process a large number of liquid droplets using projected optical images for high throughput applications. |
BibTeX:
@article{chiou_droplet_2008,
author = {Chiou, Pei-Yu and Chang, Zehao and Wu, M. C},
title = {Droplet Manipulation With Light on Optoelectrowetting Device},
journal = {Journal of Microelectromechanical Systems},
year = {2008},
volume = {17},
number = {1},
pages = {133--138},
doi = {10.1109/JMEMS.2007.904336}
}
|
| Chiou P-Y, Ohta A, Jamshidi A, Hsu H-Y and Wu M (2008), "Light-Actuated AC Electroosmosis for Nanoparticle Manipulation", Journal of Microelectromechanical Systems., June, 2008. Vol. 17(3), pp. 525-531. |
| Abstract: We present a novel light-actuated ac electroosmosis (LACE) mechanism that allows the concentration and transportation of micro- and nanoscopic particles using light-patterned dynamically reconfigured microfluidic vortices on a photoconductive surface. LACE is realized by sandwiching an aqueous liquid medium between a featureless photoconductive surface and a transparent indium tin oxide electrode. By applying an ac electrical bias with a frequency that is close to the electric double-layer relaxation frequency, a light-patterned virtual electrode can induce ac electroosmotic flow to concentrate and transport nanoscopic particles on the photoconductive surface. By integrating with a spatial light modulator such as a digital micromirror device microdisplay, we can create 31000 microfluidic vortices on a 1.3 times 1-mm2 area for massively parallel trapping of 2- and 1-mum polystyrene beads. We have also demonstrated LACE concentration and transportation of nanoscopic particles including 200- and 50-nm polystyrene beads, lambda-phage DNA molecules, and quantum dots. |
BibTeX:
@article{chiou_light-actuated_2008,
author = {Chiou, Pei-Yu and Ohta, AT. and Jamshidi, A and Hsu, Hsin-Yi and Wu, M.C.},
title = {Light-Actuated AC Electroosmosis for Nanoparticle Manipulation},
journal = {Journal of Microelectromechanical Systems},
year = {2008},
volume = {17},
number = {3},
pages = {525--531},
doi = {10.1109/JMEMS.2008.916342}
}
|
| Jamshidi A, Pauzauskie PJ, Schuck PJ, Ohta AT, Chiou PY, Chou J, Yang P and Wu MC (2008), "Dynamic manipulation and separation of individual semiconducting and metallic nanowires", Nature Photonics. Vol. 2(2), pp. 86-89. |
BibTeX:
@article{jamshidi_dynamic_2008,
author = {Jamshidi, A. and Pauzauskie, P. J. and Schuck, P. J. and Ohta, A. T. and Chiou, P. Y. and Chou, J. and Yang, P. and Wu, M. C.},
title = {Dynamic manipulation and separation of individual semiconducting and metallic nanowires},
journal = {Nature Photonics},
year = {2008},
volume = {2},
number = {2},
pages = {86--89}
}
|
| Lau E, Wong LJ, Zhao X, Chen Y-k, Chang-Hasnain C and Wu M (2008), "Bandwidth Enhancement by Master Modulation of Optical Injection-Locked Lasers", Journal of Lightwave Technology., August, 2008. Vol. 26(15), pp. 2584-2593. |
| Abstract: In normal injection-locked semiconductor lasers, the modulation signals are applied to the slave laser. In this paper, we show that modulating the master light before injection exhibits distinctive modulation dynamics and frequency response. We first present a detailed theoretical model and simulation results. Experimentally, we have successfully demonstrated both master amplitude and master phase modulation. The resulting 3-dB bandwidths have been enhanced by up to three times, exceeding 50 GHz. The resonance frequency of the combined lasers is greater than 100 GHz. |
BibTeX:
@article{lau_bandwidth_2008,
author = {Lau, E.K. and Wong, Liang Jie and Zhao, Xiaoxue and Chen, Young-kai and Chang-Hasnain, C.J. and Wu, M.C.},
title = {Bandwidth Enhancement by Master Modulation of Optical Injection-Locked Lasers},
journal = {Journal of Lightwave Technology},
year = {2008},
volume = {26},
number = {15},
pages = {2584--2593},
doi = {10.1109/JLT.2008.927192}
}
|
| Lau E, Sung H-K and Wu M (2008), "Frequency Response Enhancement of Optical Injection-Locked Lasers", Quantum Electronics, IEEE Journal of. Vol. 44(1), pp. 90-99. |
| Abstract: The modulation response of injection-locked lasers has been carefully analyzed, theoretically and experimentally, with a focus on the strong optical injection regime. We derive closed-form solutions to the relaxation oscillation (resonance) frequency and damping term, as well as the low-frequency damping term, and discuss design rules for maximizing resonance frequency and broadband performance. A phasor model is described in order to better explain the enhancement of the resonance frequency. Experimental curves match closely to theory. Record resonance frequency of 72 GHz and broadband results are shown. |
BibTeX:
@article{lau_frequency_2008,
author = {Lau, E.K. and Sung, Hyuk-Kee and Wu, M.C.},
title = {Frequency Response Enhancement of Optical Injection-Locked Lasers},
journal = {Quantum Electronics, IEEE Journal of},
year = {2008},
volume = {44},
number = {1},
pages = {90--99},
url = {10.1109/JQE.2007.910450},
doi = {10.1109/JQE.2007.910450}
}
|
| Lau EK, Zhao X, Sung H-K, Parekh D, Chang-Hasnain C and Wu MC (2008), "Strong optical injection-locked semiconductor lasers demonstrating textgreater 100-GHz resonance frequencies and 80-GHz intrinsic bandwidths", Optics Express., April, 2008. Vol. 16(9), pp. 6609-6618. |
| Abstract: By using strong optical injection locking, we report resonance frequency enhancement in excess of 100 GHz in semiconductor lasers. We demonstrate this enhancement in both distributed feedback (DFB) lasers and vertical-cavity surface-emitting lasers (VCSELs), showing the broad applicability of the technique and that the coupling Q is the figure-of-merit for resonance frequency enhancement. We have also identified the key factors that cause low-frequency roll-off in injection-locked lasers. By increasing the slave laser??s DC current bias, we have achieved a record intrinsic 3-dB bandwidth of 80 GHz in VCSELs. |
BibTeX:
@article{lau_strong_2008,
author = {Lau, Erwin K. and Zhao, Xiaoxue and Sung, Hyuk-Kee and Parekh, Devang and Chang-Hasnain, Connie and Wu, Ming C.},
title = {Strong optical injection-locked semiconductor lasers demonstrating textgreater 100-GHz resonance frequencies and 80-GHz intrinsic bandwidths},
journal = {Optics Express},
year = {2008},
volume = {16},
number = {9},
pages = {6609--6618},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-16-9-6609},
doi = {10.1364/OE.16.006609}
}
|
| Sung H-K and Wu MC (2008), "Amplitude Modulation Response and Linearity Improvement of Directly Modulated Lasers Using Ultra-Strong Injection-Locked Gain-Lever Distributed Bragg Reflector Lasers", Journal of the Optical Society of Korea., December, 2008. Vol. 12(4), pp. 303-308. |
| Abstract: Directly modulated fiber-optic links generally suffer higher link loss and larger signal distortion than externally modulated links. These result from the electron-photon conversion loss and laser modulation dynamics. As a method to overcome the drawbacks, we have experimentally demonstrated the RF performance of directly modulated, ultra-strong injection-locked gain-lever distributed Bragg reflector (DBR) lasers. The free-running DBR lasers exhibit an improved amplitude modulation efficiency of 12.4 dB under gain-lever modulation at the expense of linearity. By combining gain-lever modulation with ultra-strong optical injection locking, we can gain the benefits of both improved modulation efficiency from the gain-lever effect, plus improved linearity from injection locking. Using an injection ratio of R=11 dB, a 23.4-dB improvement in amplitude response and an 18-dB improvement in spurious-free dynamic range have been achieved. |
BibTeX:
@article{sung_amplitude_2008,
author = {Sung, Hyuk-Kee and Wu, Ming C},
title = {Amplitude Modulation Response and Linearity Improvement of Directly Modulated Lasers Using Ultra-Strong Injection-Locked Gain-Lever Distributed Bragg Reflector Lasers},
journal = {Journal of the Optical Society of Korea},
year = {2008},
volume = {12},
number = {4},
pages = {303--308},
url = {http://www.opticsinfobase.org/josk/abstract.cfm?URI=josk-12-4-303}
}
|
| Tsai J-c, Lu L-C, Hsu W-C, Sun C-W and Wu MC (2008), "Linearization of a two-axis MEMS scanner driven by vertical comb-drive actuators", Journal of Micromechanics and Microengineering., January, 2008. Vol. 18(1), pp. 015015. |
| Abstract: A driving scheme using a pair of differential voltages (Vx, Vy) over a bias voltage is proposed to linearize the dc characteristic (angle versus voltage) of a two-axis MEMS scanner. The micromirror has a gimbal-less structure and is driven by vertical comb-drive actuators in conjunction with a leverage mechanism. At an optimal bias voltage of 53 V, a linear optical scan range of ±3.2° is achieved experimentally in both the x and y directions with the differential voltages ranging from −10 V to + 10 V. |
BibTeX:
@article{tsai_linearization_2008,
author = {Tsai, Jui-che and Lu, Li-Cheng and Hsu, Wei-Chi and Sun, Chia-Wei and Wu, Ming C.},
title = {Linearization of a two-axis MEMS scanner driven by vertical comb-drive actuators},
journal = {Journal of Micromechanics and Microengineering},
year = {2008},
volume = {18},
number = {1},
pages = {015015},
url = {http://iopscience.iop.org/0960-1317/18/1/015015},
doi = {10.1088/0960-1317/18/1/015015}
}
|
| Tsai J-c, Chiou S-j, Hsieh T-l, Sun C-W, Hah D and Wu MC (2008), "Two-axis MEMS scanners with radial vertical combdrive actuators—design, theoretical analysis, and fabrication", Journal of Optics A: Pure and Applied Optics., April, 2008. Vol. 10(4), pp. 044006. |
| Abstract: We propose the employment of radial vertical combdrive actuators to implement two-axis micro-electro-mechanical systems (MEMS) scanners. The devices are designed based on a five-layer polysilicon surface micromachining process. A cross-bar spring structure consisting of lower and upper torsion springs is incorporated to achieve two rotational degrees of freedom, enabling the dual-axis rotation. Both the vertical combdrive actuators and the torsion springs are hidden underneath the mirror to achieve a small form factor. Theoretical analysis is performed for comparison of various designs. Preliminary experimental results are also obtained. |
BibTeX:
@article{tsai_two-axis_2008,
author = {Tsai, Jui-che and Chiou, Sheng-jie and Hsieh, Tien-liang and Sun, Chia-Wei and Hah, Dooyoung and Wu, Ming C.},
title = {Two-axis MEMS scanners with radial vertical combdrive actuators—design, theoretical analysis, and fabrication},
journal = {Journal of Optics A: Pure and Applied Optics},
year = {2008},
volume = {10},
number = {4},
pages = {044006},
url = {http://iopscience.iop.org/1464-4258/10/4/044006},
doi = {10.1088/1464-4258/10/4/044006}
}
|
| Valley JK, Jamshidi A, Ohta AT, Hsu HY and Wu MC (2008), "Operational regimes and physics present in optoelectronic tweezers", Journal of microelectromechanical systems: a joint IEEE and ASME publication on microstructures, microactuators, microsensors, and microsystems. Vol. 17(2), pp. 342. |
BibTeX:
@article{valley_operational_2008,
author = {Valley, J. K. and Jamshidi, A. and Ohta, A. T. and Hsu, H. Y. and Wu, M. C.},
title = {Operational regimes and physics present in optoelectronic tweezers},
journal = {Journal of microelectromechanical systems: a joint IEEE and ASME publication on microstructures, microactuators, microsensors, and microsystems},
year = {2008},
volume = {17},
number = {2},
pages = {342}
}
|
| Aguirre AD, Hertz PR, Chen Y, Fujimoto JG, Piyawattanametha W, Fan L and Wu MC (2007), "Two-axis MEMS scanning catheter for ultrahigh resolution three-dimensional and en face imaging", Optics express. Vol. 15(5), pp. 2445–2453. |
BibTeX:
@article{aguirre_two-axis_2007,
author = {Aguirre, Aaron D. and Hertz, Paul R. and Chen, Yu and Fujimoto, James G. and Piyawattanametha, Wibool and Fan, Li and Wu, Ming C.},
title = {Two-axis MEMS scanning catheter for ultrahigh resolution three-dimensional and en face imaging},
journal = {Optics express},
year = {2007},
volume = {15},
number = {5},
pages = {2445–2453},
url = {http://www.opticsinfobase.org/abstract.cfm?uri=OE-15-5-2445}
}
|
| Lau EK, Sung H-K and Wu MC (2007), "Scaling of resonance frequency for strong injection-locked lasers", Optics Letters., December, 2007. Vol. 32(23), pp. 3373-3375. |
| Abstract: It has been shown that strong optical injection locking can significantly enhance the resonance frequency of semiconductor lasers. In this Letter, we describe the trade-off between the maximum resonance frequency enhancement and the quality factor (Q) of the lossless laser cavity and show that the time-bandwidth product (product of photon lifetime and maximum resonance frequency) is equal to one half the square root of the external power injection ratio. The theoretical model agrees well with our experimental data. |
BibTeX:
@article{lau_scaling_2007,
author = {Lau, Erwin K. and Sung, Hyuk-Kee and Wu, Ming C.},
title = {Scaling of resonance frequency for strong injection-locked lasers},
journal = {Optics Letters},
year = {2007},
volume = {32},
number = {23},
pages = {3373--3375},
url = {http://ol.osa.org/abstract.cfm?URI=ol-32-23-3373},
doi = {10.1364/OL.32.003373}
}
|
| Ohta AT, Chiou PY, Han TH, Liao JC, Bhardwaj U, McCabe ERB, Yu F, Sun R and Wu MC (2007), "Dynamic Cell and Microparticle Control via Optoelectronic Tweezers", Microelectromechanical Systems, Journal of. Vol. 16(3), pp. 491-499. |
BibTeX:
@article{ohta_dynamic_2007,
author = {Ohta, A. T. and Chiou, P. Y. and Han, T. H. and Liao, J. C. and Bhardwaj, U. and McCabe, E. R. B. and Yu, F. and Sun, R. and Wu, M. C.},
title = {Dynamic Cell and Microparticle Control via Optoelectronic Tweezers},
journal = {Microelectromechanical Systems, Journal of},
year = {2007},
volume = {16},
number = {3},
pages = {491--499},
url = {file://C:Documents and SettingsWU-PCMy DocumentsMy PublicationsNew Publications.DataOhta-Dynamic Cell & Microparticl-1227744003/Ohta-Dynamic Cell & Microparticle Control via OET-JMEMS 2007.pdf}
}
|
| Ohta AT, Pei-Yu C, Phan HL, Sherwood SW, Yang JM, Lau ANK, Hsu HY, Jamshidi A and Wu MC (2007), "Optically controlled cell discrimination and trapping using optoelectronic tweezers", IEEE Journal of Selected Topics in Quantum Electronics. Vol. 13(2), pp. 235-43. |
| Abstract: Optoelectronic tweezers (OET) provide a powerful tool for the manipulation of micro- and nanoparticles. The OET device produces an optically controlled dielectrophoretic force, allowing complex dynamic manipulation patterns using light intensities up to 100 000 times lower than that of optical tweezers. Using OET, we demonstrate the separation of live and dead human B cells, and the separation of HeLa and Jurkat cells. We also present, for the first time, a modified single-sided OET device that promises to facilitate the integration of OET and microfluidics. Unlike standard OET, this single-sided OET device produces electric fields that are oriented parallel to the plane of the device. We demonstrate the manipulation of polystyrene beads using this new single-sided OET device, and discuss its capabilities (31 References). |
BibTeX:
@article{ohta_optically_2007,
author = {Ohta, A. T. and Pei-Yu, Chiou and Phan, H. L. and Sherwood, S. W. and Yang, J. M. and Lau, A. N. K. and Hsu, H. Y. and Jamshidi, A. and Wu, M. C.},
title = {Optically controlled cell discrimination and trapping using optoelectronic tweezers},
journal = {IEEE Journal of Selected Topics in Quantum Electronics},
year = {2007},
volume = {13},
number = {2},
pages = {235--43},
url = {file://C:Documents and SettingsWU-PCMy DocumentsMy PublicationsNew Publications.DataOhta-Lateral OET-JSTQE 2007-4030241283/Ohta-Lateral OET-JSTQE 2007.pdf}
}
|
| Ohta AT, Jamshidi A, Valley JK, Hsu HY and Wu MC (2007), "Optically actuated thermocapillary movement of gas bubbles on an absorbing substrate", Applied Physics Letters. Vol. 91, pp. 074103. |
BibTeX:
@article{ohta_optically_2007-1,
author = {Ohta, A. T. and Jamshidi, A. and Valley, J. K. and Hsu, H. Y. and Wu, M. C.},
title = {Optically actuated thermocapillary movement of gas bubbles on an absorbing substrate},
journal = {Applied Physics Letters},
year = {2007},
volume = {91},
pages = {074103},
url = {file://C:Documents and SettingsWU-PCMy DocumentsMy PublicationsNew Publications.DataOhta-Optically Actuated Thermocapillar-0975539715/Ohta-Optically Actuated Thermocapillary Movement-APL 2007.pdf}
}
|
| Sung H-K, Lau E and Wu M (2007), "Optical Properties and Modulation Characteristics of Ultra-Strong Injection-Locked Distributed Feedback Lasers", IEEE Journal of Selected Topics in Quantum Electronics. Vol. 13(5), pp. 1215-1221. |
| Abstract: The optical properties and the frequency responses of ultrastrong (injection ratio textgreater 10 dB) injection-locked distributed feedback lasers are investigated experimentally and theoretically. We have observed three distinctive modulation regimes under different frequency detuning between the master and the slave lasers. At large negative frequency detuning, the laser exhibits enhanced modulation efficiency at low frequencies. At intermediate frequency detuning, a flat frequency response with large 3 dB bandwidth is observed. At large positive frequency detuning, the modulation response shows a pronounced resonance peak at high frequencies. These phenomena can be explained by the resonance enhancement of the slave laser cavity mode, with the resonance frequency equal to the difference between the injection-locked frequency and the cavity mode. The experimental results agree well with theoretical calculations based on three coupled rate equations. Depending on the applications, the injection locking conditions can be optimized to achieve high RF link gain, broadband, or high resonance frequency operations. |
BibTeX:
@article{sung_optical_2007,
author = {Sung, Hyuk-Kee and Lau, E.K. and Wu, M.C.},
title = {Optical Properties and Modulation Characteristics of Ultra-Strong Injection-Locked Distributed Feedback Lasers},
journal = {IEEE Journal of Selected Topics in Quantum Electronics},
year = {2007},
volume = {13},
number = {5},
pages = {1215--1221},
doi = {10.1109/JSTQE.2007.905153}
}
|
| Sung H-K, Lau E and Wu M (2007), "Optical Single Sideband Modulation Using Strong Optical Injection-Locked Semiconductor Lasers", IEEE Photonics Technology Letters. Vol. 19(13), pp. 1005-1007. |
| Abstract: We report on the experimental demonstration of optical single sideband (SSB) modulation using a directly modulated semiconductor laser under strong optical injection-locking. Modulation sidebands with 15-dB power ratio between the lower and upper sidebands have been achieved. The longer wavelength sideband is resonantly amplified by the injection-locked laser cavity mode. The radio-frequency performance of the optical SSB after 80-km fiber transmission is significantly improved compared with a typical symmetric sideband modulation of a free-running laser. A 622-Mb/s data transmission on a 20-GHz subcarrier is demonstrated over an 80-km fiber link. |
BibTeX:
@article{sung_optical_2007-1,
author = {Sung, Hyuk-Kee and Lau, E.K. and Wu, M.C.},
title = {Optical Single Sideband Modulation Using Strong Optical Injection-Locked Semiconductor Lasers},
journal = {IEEE Photonics Technology Letters},
year = {2007},
volume = {19},
number = {13},
pages = {1005--1007},
doi = {10.1109/LPT.2007.898760}
}
|
| Tsai J-c, Yin C-Y, Sun C-W and Wu MC (2007), "Analysis of the interchannel response in a MEMS 1 × N2 wavelength-selective switch", Applied Optics., June, 2007. Vol. 46(16), pp. 3227-3232. |
| Abstract: A theoretical model based on Fourier optics and the power-coupling overlap integral is built to investigate the interchannel response in a micro-electro-mechanical systems 1×N2 wavelength-selective switch. The simulation results demonstrate that the interchannel response depends significantly on the output port location and the radius of curvature of the micromirrors. For the output originally aligned with the input along the dispersion direction, it is possible to achieve interchannel-response suppression by rotating the two-dimensional (2D) collimator array by a slight angle, e.g., 20°. Experimental results under different conditions are also shown. |
BibTeX:
@article{tsai_analysis_2007,
author = {Tsai, Jui-che and Yin, Chun-Yi and Sun, Chia-Wei and Wu, Ming C.},
title = {Analysis of the interchannel response in a MEMS 1 × N2 wavelength-selective switch},
journal = {Applied Optics},
year = {2007},
volume = {46},
number = {16},
pages = {3227--3232},
url = {http://ao.osa.org/abstract.cfm?URI=ao-46-16-3227},
doi = {10.1364/AO.46.003227}
}
|
| Yao J, Leuenberger D, Lee M-CM and Wu M (2007), "Silicon Microtoroidal Resonators With Integrated MEMS Tunable Coupler", IEEE Journal of Selected Topics in Quantum Electronics. Vol. 13(2), pp. 202-208. |
| Abstract: A single crystalline silicon microtoroidal resonator with integrated MEMS-actuated tunable optical coupler is demonstrated for the first time. It is fabricated by combining hydrogen annealing and wafer bonding processes. The device operates in all three coupling regimes: under-, critical, and over-coupling. We have also developed a comprehensive model based on time-domain coupling theory. The experimental and theoretical results agree very well. The quality factor (Q) is extracted by fitting the experimental curve with the model. The unloaded Q is as high as 110 000, and the loaded Q is continuously tunable from 110 000 to 5400. The extinction ratio of the transmittance is 22.4 dB. This device can be used as a building block of resonator-based reconfigurable photonic integrated circuits |
BibTeX:
@article{yao_silicon_2007,
author = {Yao, Jin and Leuenberger, David and Lee, Ming-Chang M. and Wu, M.C.},
title = {Silicon Microtoroidal Resonators With Integrated MEMS Tunable Coupler},
journal = {IEEE Journal of Selected Topics in Quantum Electronics},
year = {2007},
volume = {13},
number = {2},
pages = {202--208},
doi = {10.1109/JSTQE.2007.893743}
}
|
| Zhang B, Leuenberger D, Lee M-CM, Willner A and Wu M (2007), "Experimental Demonstration of Dynamic Bandwidth Allocation Using a MEMS-Actuated Bandwidth-Tunable Microdisk Resonator Filter", IEEE Photonics Technology Letters., October, 2007. Vol. 19(19), pp. 1508-1510. |
| Abstract: A novel bandwidth-tunable optical filter based on a microelectromechanical-system-actuated microdisk resonator is utilized for dynamic bandwidth allocation. The filter bandwidth can be dynamically adjusted by voltage tuning the gap spacing between the two waveguides and microdisk. Three key applications of dynamic bandwidth allocation are demonstrated experimentally. Matched optical filtering is achieved on 5-Gb/s nonreturn-to-zero (NRZ) signals with error-free ( 10-9 bit-error-rate) data transmission. Reconfigurable channel banding of three 2.5-Gb/s NRZ signals is demonstrated by either routing a single or a group of data channels. Wavelength demultiplexing of three channels under the worst-case scenario shows 14.5-dB suppression with error-free operation. |
BibTeX:
@article{zhang_experimental_2007,
author = {Zhang, Bo and Leuenberger, David and Lee, Ming-Chang M. and Willner, AE. and Wu, M.C.},
title = {Experimental Demonstration of Dynamic Bandwidth Allocation Using a MEMS-Actuated Bandwidth-Tunable Microdisk Resonator Filter},
journal = {IEEE Photonics Technology Letters},
year = {2007},
volume = {19},
number = {19},
pages = {1508--1510},
doi = {10.1109/LPT.2007.903872}
}
|
| Zhao X, Parekh D, Lau EK, Sung H-K, Wu MC, Hofmann W, Amann MC and Chang-Hasnain CJ (2007), "Novel cascaded injection-locked 1.55-um VCSELs with 66 GHz modulation bandwidth", Optics Express., October, 2007. Vol. 15(22), pp. 14810-14816. |
| Abstract: We demonstrate a novel cascaded configuration of optically injection-locked (COIL) VCSELs, which enables a wide and tailorable direct modulation bandwidth. Up to 66 GHz bandwidth is achieved using VCSELs with an original, free-running 10 GHz bandwidth. Different configurations of cascading are discussed in detail with the focus on optimizing the modulation bandwidth. We also discuss scaling capability of this technique to achieve tailorable modulation response. |
BibTeX:
@article{zhao_novel_2007,
author = {Zhao, Xiaoxue and Parekh, Devang and Lau, Erwin K. and Sung, Hyuk-Kee and Wu, Ming C. and Hofmann, Werner and Amann, Markus C. and Chang-Hasnain, Connie J.},
title = {Novel cascaded injection-locked 1.55-um VCSELs with 66 GHz modulation bandwidth},
journal = {Optics Express},
year = {2007},
volume = {15},
number = {22},
pages = {14810--14816},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-15-22-14810},
doi = {10.1364/OE.15.014810}
}
|
| Lee M-CM, Hah D, Lau E, Toshiyoshi H and Wu M (2006), "MEMS-actuated photonic crystal switches", IEEE Photonics Technology Letters., January, 2006. Vol. 18(2), pp. 358-360. |
| Abstract: A compact guided-wave optical switch is realized by integrating one-dimensional photonic crystals with microelectromechanical systems (MEMS) actuators. The ON-OFF switching is achieved by physically moving a photonic crystal defect. Experimental results show an extinction ratio of 11 dB at 1.56-μm wavelength and a 0.5-ms time constant of the step response. |
BibTeX:
@article{lee_mems-actuated_2006,
author = {Lee, Ming-Chang M. and Hah, D. and Lau, E.K. and Toshiyoshi, H. and Wu, Ming},
title = {MEMS-actuated photonic crystal switches},
journal = {IEEE Photonics Technology Letters},
year = {2006},
volume = {18},
number = {2},
pages = {358--360},
doi = {10.1109/LPT.2005.861957}
}
|
| Lee MC and Wu MC (2006), "Thermal annealing in hydrogen for 3-D profile transformation on silicon-on-insulator and sidewall roughness reduction", Journal of Microelectromechanical Systems., April, 2006. Vol. 15(2), pp. 338- 343. |
| Abstract: A fast, effective process using hydrogen annealing is introduced to perform profile transformation on silicon-on-insulator (SOI) and to reduce sidewall roughness on silicon surfaces. By controlling the dimensions of as-etched structures, microspheres with 1 μm radii, submicron wires with 0.5 μm radii, and a microdisk toroid with 0.2 μm toroidal radius have been successfully demonstrated on SOI substrates. Utilizing this technique, we also observe the root-mean-square (rms) sidewall roughness dramatically reduced from 20 to 0.26 nm. A theoretical model is presented to analyze the profile transformation, and experimental results show this process can be engineered by several parameters including temperature, pressure, and time. |
BibTeX:
@article{lee_thermal_2006,
author = {Lee, M. -C.M and Wu, M. C},
title = {Thermal annealing in hydrogen for 3-D profile transformation on silicon-on-insulator and sidewall roughness reduction},
journal = {Journal of Microelectromechanical Systems},
year = {2006},
volume = {15},
number = {2},
pages = {338-- 343},
doi = {10.1109/JMEMS.2005.859092}
}
|
| Lee M-CM and Wu MC (2006), "Tunable coupling regimes of silicon microdisk resonators using MEMS actuators", Optics Express., May, 2006. Vol. 14(11), pp. 4703-4712. |
| Abstract: Tunable coupling regimes of a silicon microdisk resonator controlled by MEMS (microelectromechanical system) actuation are demonstrated for the first time. By varying the gap spacing between the waveguide and the disk, this microresonator can dynamically operate in either under-, ciritcal or over-coupling regime. The waveguide transmittance is suppressed by 30 dB in critical coupling, and the quality factor of the microdisk is measured to be as high as 105. Additionally, the microdisk presents tunable group delay from 27 ps to 65 ps, and tunable group velocity dispersion from 185 ps/nm to 1200 ps/nm. Waveguides, microdisks and actuators are all integrated on a silicon-on-insulator (SOI) substrate. This compact device exhibits the promise to construct resonator-based reconfigurable photonic integrated circuits. |
BibTeX:
@article{lee_tunable_2006,
author = {Lee, Ming-Chang M. and Wu, Ming C.},
title = {Tunable coupling regimes of silicon microdisk resonators using MEMS actuators},
journal = {Optics Express},
year = {2006},
volume = {14},
number = {11},
pages = {4703--4712},
url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-14-11-4703},
doi = {10.1364/OE.14.004703}
}
|
| Lee M-CM and Wu MC (2006), "Variable bandwidth of dynamic add-drop filters based on coupling-controlled microdisk resonators", Optics Letters., August, 2006. Vol. 31(16), pp. 2444-2446. |
| Abstract: Dynamic add-drop filters with variable bandwidth are demonstrated on microelectromechanical-system (MEMS)-actuated microdisk resonators for what is believed to be the first time. The tuning mechanism is based on a variable power coupling ratio that is controlled by varying the gap spacing between the waveguide and the microdisk through MEMS actuators. The results show wavelength switching with an extinction ratio of 20 dB and a tunable bandwidth ranging from 12 to 27 GHz. These dual functions were realized using the device with the operation voltage varying between 0 and 35 V. |
BibTeX:
@article{lee_variable_2006,
author = {Lee, Ming-Chang M. and Wu, Ming C.},
title = {Variable bandwidth of dynamic add-drop filters based on coupling-controlled microdisk resonators},
journal = {Optics Letters},
year = {2006},
volume = {31},
number = {16},
pages = {2444--2446},
url = {http://ol.osa.org/abstract.cfm?URI=ol-31-16-2444},
doi = {10.1364/OL.31.002444}
}
|
| Tsai J-C, Huang ST-Y, Hah D and Wu M (2006), "1xN2 wavelength-selective switch with two cross-scanning one-axis analog micromirror arrays in a 4-f optical system", Journal of Lightwave Technology., February, 2006. Vol. 24(2), pp. 897-903. |
| Abstract: A new high-port-count wavelength-selective switch (WSS) has been realized using two cross-scanning one-axis analog micromirror arrays in a 4-f optical system. The number of output ports is increased from N to N2, where N is the maximum linear port count limited by optical diffraction. Using surface-micromachined micromirrors with hidden vertical comb drives, large scan angles (textgreater±5° mechanical), low drive voltages (7 V), and high fill factors (textgreater 96.25 are achieved for both scanning mirrors. Experimental results for WSS are demonstrated using both two-dimensional (2-D) array of discrete collimators and monolithic 2-D collimator array. A fiber-to-fiber insertion loss ranging from 6 to 18 dB and a switching time of textless700 μs have been achieved. |
BibTeX:
@article{tsai_1xn2_2006,
author = {Tsai, Jui-Che and Huang, Sophia Ting-Yu and Hah, D. and Wu, M.C.},
title = {1xN2 wavelength-selective switch with two cross-scanning one-axis analog micromirror arrays in a 4-f optical system},
journal = {Journal of Lightwave Technology},
year = {2006},
volume = {24},
number = {2},
pages = {897--903},
doi = {10.1109/JLT.2005.861915}
}
|
| Tsai J and Wu MC (2006), "A high port-count wavelength-selective switch using a large scan-angle, high fill-factor, two-axis MEMS scanner array", IEEE Photonics Technology Letters. Vol. 18(13), pp. 1439-1441. |
BibTeX:
@article{tsai_high_2006,
author = {Tsai, J. and Wu, M. C.},
title = {A high port-count wavelength-selective switch using a large scan-angle, high fill-factor, two-axis MEMS scanner array},
journal = {IEEE Photonics Technology Letters},
year = {2006},
volume = {18},
number = {13},
pages = {1439--1441}
}
|
| Wu MC, Solgaard O and Ford JE (2006), "Optical MEMS for Lightwave Communication", Journal of Lightwave Technology., December, 2006. Vol. 24(12), pp. 4433-4454. |
| Abstract: The intensive investment in optical microelectromechanical systems (MEMS) in the last decade has led to many successful components that satisfy the requirements of lightwave communication networks. In this paper, we review the current state of the art of MEMS devices and subsystems for lightwave communication applications. Depending on the design, these components can either be broadband (wavelength independent) or wavelength selective. Broadband devices include optical switches, crossconnects, optical attenuators, and data modulators, while wavelength-selective components encompass wavelength add/drop multiplexers, wavelength-selective switches and crossconnects, spectral equalizers, dispersion compensators, spectrometers, and tunable lasers. Integration of MEMS and planar lightwave circuits, microresonators, and photonic crystals could lead to further reduction in size and cost |
BibTeX:
@article{wu_optical_2006,
author = {Wu, M. C and Solgaard, O. and Ford, J. E},
title = {Optical MEMS for Lightwave Communication},
journal = {Journal of Lightwave Technology},
year = {2006},
volume = {24},
number = {12},
pages = {4433--4454},
doi = {10.1109/JLT.2006.886405}
}
|
| Chiou PY, Ohta AT and Wu MC (2005), "Massively parallel manipulation of single cells and microparticles using optical images", Nature. Vol. 436(7049), pp. 370-372. |
BibTeX:
@article{chiou_massively_2005,
author = {Chiou, P. Y. and Ohta, A. T. and Wu, M. C.},
title = {Massively parallel manipulation of single cells and microparticles using optical images},
journal = {Nature},
year = {2005},
volume = {436},
number = {7049},
pages = {370--372},
url = {file://C:Documents and SettingsWU-PCMy DocumentsMy PublicationsNew Publications.DataChiou-OET-Nature 2005-1380666886/Chiou-OET-Nature 2005.pdf}
}
|
| Lee M-C and Wu M (2005), "MEMS-actuated microdisk resonators with variable power coupling ratios", IEEE Photonics Technology Letters., May, 2005. Vol. 17(5), pp. 1034-1036. |
BibTeX:
@article{lee_mems-actuated_2005,
author = {Lee, M.-C.M. and Wu, M.C.},
title = {MEMS-actuated microdisk resonators with variable power coupling ratios},
journal = {IEEE Photonics Technology Letters},
year = {2005},
volume = {17},
number = {5},
pages = {1034--1036},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=1424091},
doi = {10.1109/LPT.2005.845772}
}
|
| Piyawattanametha W, Patterson P, Hah D, Toshiyoshi H and Wu M (2005), "Surface- and bulk- micromachined two-dimensional scanner driven by angular vertical comb actuators", Journal of Microelectromechanical Systems., December, 2005. Vol. 14(6), pp. 1329-1338. |
| Abstract: In this paper, we present the design, fabrication, and measurements of a two-dimensional (2-D) optical scanner with electrostatic angular vertical comb (AVC) actuators. The scanner is realized by combining a foundry-based surface-micromachining process (Multi-User MEMS Processes-MUMPs) with a three-mask deep-reactive ion-etching (DRIE) postfabrication process. The surface-micromachining provides versatile mechanical design and electrical interconnect while the bulk micromachining offers high-aspect ratio structures leading to flat mirrors and high-force, large-displacement actuators. The scanner achieves dc mechanical scanning ranges of ±6.2° (at 55 Vdc) and ±4.1° (at 50 Vdc) for the inner and outer gimbals, respectively. The resonant frequencies are 315 and 144 Hz for the inner and the outer axes, respectively. The 1-mm-diameter mirror has a radius of curvature of over 50 cm. [1454]. |
BibTeX:
@article{piyawattanametha_surface-_2005,
author = {Piyawattanametha, W. and Patterson, P.R. and Hah, D. and Toshiyoshi, H. and Wu, M.C.},
title = {Surface- and bulk- micromachined two-dimensional scanner driven by angular vertical comb actuators},
journal = {Journal of Microelectromechanical Systems},
year = {2005},
volume = {14},
number = {6},
pages = {1329--1338},
doi = {10.1109/JMEMS.2005.859073}
}
|
| Tsai J-C and Wu M (2005), "Gimbal-less MEMS two-axis optical scanner array with high fill-factor", Journal of Microelectromechanical Systems., December, 2005. Vol. 14(6), pp. 1323-1328. |
| Abstract: In this paper, we report on a MEMS-based two-axis optical scanner array with a high fill factor (textgreater96, large mechanical scan angles (±4.4° and ±3.4°), and high resonant frequencies (20.7 kHz). The devices are fabricated using SUMMiT-V, a five-layer surface-micromachining process. High fill factor, which is important for 1×N2 wavelength-selective switches (WSSs), is achieved by employing crossbar torsion springs underneath the mirror, eliminating the need for gimbal structures. The proposed mirror structure can be readily extended to two-dimensional (2-D) array for adaptive optics applications. In addition to two-axis rotation, piston motion with a stroke of 0.8 μm is also achieved. [1496]. |
BibTeX:
@article{tsai_gimbal-less_2005,
author = {Tsai, Jui-Che and Wu, M.C.},
title = {Gimbal-less MEMS two-axis optical scanner array with high fill-factor},
journal = {Journal of Microelectromechanical Systems},
year = {2005},
volume = {14},
number = {6},
pages = {1323--1328},
doi = {10.1109/JMEMS.2005.859193}
}
|
| Fujino M, Patterson PR, Nguyen H, Piyawattanametha W and Wu MC (2004), "Monolithically cascaded micromirror pair driven by angular vertical combs for two-axis scanning", IEEE Journal of Selected Topics in Quantum Electronics. Vol. 10(3), pp. 492-497. |
BibTeX:
@article{fujino_monolithically_2004,
author = {Fujino, M. and Patterson, P. R. and Nguyen, H. and Piyawattanametha, W. and Wu, M. C.},
title = {Monolithically cascaded micromirror pair driven by angular vertical combs for two-axis scanning},
journal = {IEEE Journal of Selected Topics in Quantum Electronics},
year = {2004},
volume = {10},
number = {3},
pages = {492--497}
}
|
| Gupta V, Snow R, Wu M, Jain A and Tsai J-C (2004), "Recovery of stiction-failed MEMS structures using laser-induced stress waves", Journal of Microelectromechanical Systems., August, 2004. Vol. 13(4), pp. 696-700. |
| Abstract: Stiction, or adhesion between suspended structures and the underlying surface, is a hurdle in batch fabricating long, freestanding MEMS structures. A novel technique is presented in this paper to release stiction. In this technique, a nanosecond rise time stress wave is launched on the backside of the Si substrate by impinging a 2.5 ns-duration Nd:YAG laser pulse onto a 3-mm-dia area. The compressive stress wave propagates through the Si substrate and arrives at the site of several stiction-failed cantilevers on the front Si surface. The compressive stress wave propagates through the cantilevered structures and is reflected into a tensile wave from their free surfaces. The returning tensile wave pries off the interface, releasing the cantilevers. The procedure is demonstrated on a MEMS chip with stiction-failed cantilevers with varying lengths from 100 μm to 1000 μm. The threshold laser energy to release stiction increased linearly with cantilever lengths. Beam recovery began at a laser fluence of 11 kJ/m2 laser energy. 70% of the tested beams had been recovered after impingement with a fluence of 26 kJ/m2. After the highest applied laser fluence of 40 kJ/m2, 90% of the tested beams had been recovered. No damage to the structures or surrounding features was observed below 40 kJ/m2. Because of rather low laser fluence, no thermal damage to the back surface of Si was noted. Since it literally takes few seconds to release stiction, the proposed technique can be implemented in MEMS foundry, and for repair of in-use stiction failed MEMS devices. |
BibTeX:
@article{gupta_recovery_2004,
author = {Gupta, Vijay and Snow, R. and Wu, M.C. and Jain, A and Tsai, Jui-Che},
title = {Recovery of stiction-failed MEMS structures using laser-induced stress waves},
journal = {Journal of Microelectromechanical Systems},
year = {2004},
volume = {13},
number = {4},
pages = {696--700},
doi = {10.1109/JMEMS.2004.832185}
}
|
| Hah D, Huang ST-Y, Tsai J-C, Toshiyoshi H and Wu M (2004), "Low-voltage, large-scan angle MEMS analog micromirror arrays with hidden vertical comb-drive actuators", Journal of Microelectromechanical Systems., April, 2004. Vol. 13(2), pp. 279-289. |
| Abstract: This paper reports on novel polysilicon surface-micromachined one-dimensional (1-D) analog micromirror arrays fabricated using Sandia's ultraplanar multilevel MEMS technology-V (SUMMiT-V) process. Large continuous DC scan angle (23.6° optical) and low-operating voltage (6 V) have been achieved using vertical comb-drive actuators. The actuators and torsion springs are placed underneath the mirror (137×120 μm2) to achieve high fill-factor (91. The measured resonant frequency of the mirror ranges from 3.4 to 8.1 kHz. The measured DC scanning characteristics and resonant frequencies agree well with theoretical values. The rise time is 120 μs and the fall time is 380 μs. The static scanning characteristics show good uniformity (textless±3.2 for a 1 × 10 array with a mirror pitch of 150 μm. The mechanical crosstalk between adjacent mirrors is less than 37 dB. These micromirror arrays have applications in 1×N wavelength-selective switches and N×N wavelength-selective crossconnects in wavelength-division multiplexing (WDM) networks. |
BibTeX:
@article{hah_low-voltage_2004,
author = {Hah, D. and Huang, Sophia Ting-Yu and Tsai, Jui-Che and Toshiyoshi, H. and Wu, M.C.},
title = {Low-voltage, large-scan angle MEMS analog micromirror arrays with hidden vertical comb-drive actuators},
journal = {Journal of Microelectromechanical Systems},
year = {2004},
volume = {13},
number = {2},
pages = {279--289},
doi = {10.1109/JMEMS.2004.825314}
}
|
| Hah D, Patterson P, Nguyen H, Toshiyoshi H and Wu M (2004), "Theory and experiments of angular vertical comb-drive actuators for scanning micromirrors", IEEE Journal of Selected Topics in Quantum Electronics., May, 2004. Vol. 10(3), pp. 505-513. |
| Abstract: We report on the theory and experiments of scanning micromirrors with angular vertical comb-drive (AVC) actuators. Parametric analyses of rotational vertical comb-drive actuators using a hybrid model that combines two-dimensional finite-element solutions with analytic formulations are described. The model is applied to both AVC and staggered vertical comb-drive (SVC) actuators. Detailed design tradeoffs and conditions for pull-in-free operations are discussed. Our simulation results show that the fringe fields play an important role in the estimation of maximum continuous rotation angles, particularly for combs with thin fingers, and that the maximum scan angle of the AVC is up to 60% larger than that of the SVC. Experimentally, a large dc continuous scan angle of 28.8° (optical) has been achieved with a moderate voltage (65 V) for a 1-mm-diameter scanning micromirror with AVC actuators. Excellent agreement between the experimental data and the theoretical simulations has been obtained. |
BibTeX:
@article{hah_theory_2004,
author = {Hah, D. and Patterson, P.R. and Nguyen, H.D. and Toshiyoshi, H. and Wu, M.C.},
title = {Theory and experiments of angular vertical comb-drive actuators for scanning micromirrors},
journal = {IEEE Journal of Selected Topics in Quantum Electronics},
year = {2004},
volume = {10},
number = {3},
pages = {505--513},
doi = {10.1109/JSTQE.2004.829200}
}
|
| Nguyen H, Hah D, Patterson P, Chao R, Piyawattanametha W, Lau E and Wu M (2004), "Angular vertical comb-driven tunable capacitor with high-tuning capabilities", Journal of Microelectromechanical Systems., June, 2004. Vol. 13(3), pp. 406-413. |
| Abstract: This paper reports on a novel tunable capacitor with electrostatic angular vertical comb-drive (AVC) actuators. The AVC tunable capacitor creates a large offset in comb fingers through a small rotation angle-an advantage not found in conventional lateral comb-drive devices. High capacitance and large continuous tuning ratio is achieved in a compact device area. The largest tuning varactor demonstrates capacitance values between 0.27-8.6 pF-a tuning ratio of more than 31:1, the highest ever reported. The maximum quality factor Q is 273 at 1 GHz near the minimum capacitance value. |
BibTeX:
@article{nguyen_angular_2004,
author = {Nguyen, H.D. and Hah, D. and Patterson, P.R. and Chao, Rumin and Piyawattanametha, W. and Lau, E.K. and Wu, M.C.},
title = {Angular vertical comb-driven tunable capacitor with high-tuning capabilities},
journal = {Journal of Microelectromechanical Systems},
year = {2004},
volume = {13},
number = {3},
pages = {406--413},
doi = {10.1109/JMEMS.2004.828741}
}
|
| Paik J-A, Fan S-K, Chang H, Kim C-J, Wu MC and Dunn B (2004), "Development of spin coated mesoporous oxide films for MEMS structures", Journal of electroceramics. Vol. 13(1-3), pp. 423–428. |
BibTeX:
@article{paik_development_2004,
author = {Paik, Jong-Ah and Fan, Shih-Kang and Chang, Hsin and Kim, Chang-Jin and Wu, Ming C. and Dunn, Bruce},
title = {Development of spin coated mesoporous oxide films for MEMS structures},
journal = {Journal of electroceramics},
year = {2004},
volume = {13},
number = {1-3},
pages = {423–428},
url = {http://link.springer.com/article/10.1007/s10832-004-5136-5}
}
|
| Tsai J-C, Huang S, Hah D, Toshiyoshi H and Wu M (2004), "Open-loop operation of MEMS-based 1 times;N wavelength-selective switch with long-term stability and repeatability", IEEE Photonics Technology Letters. Vol. 16(4), pp. 1041-1043. |
| Abstract: We report on a microelectromechanical-systems (MEMS)-based 1×N wavelength-selective switch (WSS) with excellent open-loop stability and repeatability. The optical power fluctuation of the WSS is textless±0.0035 dB over a 3.5-h period. The variation of optical power during 30 ON-OFF switching periods is textless±0.0026 dB. Experiments were also performed on the analog MEMS mirror. The stability and repeatability are ±0.00085° and ±0.0013°, respectively. |
BibTeX:
@article{tsai_open-loop_2004,
author = {Tsai, Jui-Che and Huang, S. and Hah, D. and Toshiyoshi, H. and Wu, M.C.},
title = {Open-loop operation of MEMS-based 1 times;N wavelength-selective switch with long-term stability and repeatability},
journal = {IEEE Photonics Technology Letters},
year = {2004},
volume = {16},
number = {4},
pages = {1041--1043},
doi = {10.1109/LPT.2004.824652}
}
|
| Chiou PY, Moon H, Toshiyoshi H, Kim C-J and Wu MC (2003), "Light actuation of liquid by optoelectrowetting", Sensors & Actuators A-Physical. Vol. A104(3), pp. 222-8. |
| Abstract: Optical actuation of liquid droplets has been experimentally demonstrated for the first time using a novel optoelectrowetting (OEW) principle. The optoelectrowetting surface is realized by integrating a photoconductive material underneath a two-dimensional array of electrowetting electrodes. Contact angle change as large as 30 degrees has been achieved when illuminated by a light beam with an intensity of 65 mW/cm/sup 2/. A micro-liter droplet of deionized water has been successfully transported by a 4 mW laser beam across a 1 cm * 1 cm OEW surface. The droplet speed is measured to be 7 mm/s. Light actuation enables complex microfluidic functions to be performed on a single chip without encountering the wiring bottleneck of two-dimensional array of electrowetting electrodes. (11 References). |
BibTeX:
@article{chiou_light_2003,
author = {Chiou, Pei Yu and Moon, Heyjin and Toshiyoshi, H. and Kim, Chang-Jin and Wu, M. C.},
title = {Light actuation of liquid by optoelectrowetting},
journal = {Sensors & Actuators A-Physical},
year = {2003},
volume = {A104},
number = {3},
pages = {222--8},
url = {file://C:Documents and SettingsWU-PCMy DocumentsMy PublicationsNew Publications.DataChiou - Ligh actuation of liquid b-3096285700/Chiou - Ligh actuation of liquid by optoelectrowetting.pdf}
}
|
| Murthy S, Kim S-J, Jung T, Wang Z-Z, Hsin W, Itoh T and Wu M (2003), "Backward-wave cancellation in distributed traveling-wave photodetectors", Journal of Lightwave Technology., December, 2003. Vol. 21(12), pp. 3071-3077. |
| Abstract: This paper describes the design, fabrication, and measurement of backward-wave-cancelled distributed traveling-wave photodetectors. One of the fundamental issues in traveling-wave photodetectors is the generation of backward-waves, which reduces bandwidth or, in the case of matched input termination, reduces their radio-frequency (RF) efficiencies by up to 6 dB. We report a traveling-wave photodetector with multisection coplanar strip transmission lines. The reflections at the discontinuities of the transmission line cancel the backward propagating waves exactly. The bandwidth reduction due to backward-waves is eliminated without sacrificing the RF efficiency. We have demonstrated a broadband backward-wave-cancelled traveling-wave photodetector with three discrete photodiodes. The photodetector is realized in InGaAs/InGaAsP/InP material systems and operates at 1.55 μm. A 3-dB bandwidth of 38 GHz and a linear RF output of -1 dBm at 40 GHz have been achieved. The experimental results agree very well with the theoretical calculations. |
BibTeX:
@article{murthy_backward-wave_2003,
author = {Murthy, S. and Kim, Seong-Jin and Jung, T. and Wang, Zhi-Zhi and Hsin, Wei and Itoh, T. and Wu, M.C.},
title = {Backward-wave cancellation in distributed traveling-wave photodetectors},
journal = {Journal of Lightwave Technology},
year = {2003},
volume = {21},
number = {12},
pages = {3071--3077},
doi = {10.1109/JLT.2003.819804}
}
|
| Toshiyoshi H, Su G-DJ, LaCosse J and Wu MC (2003), "A Surface Micromachined Optical Scanner ArrayUsing Photoresist Lenses Fabricated by aThermal Reflow Process", Journal of Lightwave Technology., July, 2003. Vol. 21(7), pp. 1700. |
| Abstract: This paper presents the design, fabrication, and operation of a newly developed micromechanical optical scanner array using a translating microlens. We have used photoresist reflow techinique to form a microlens on a surface micromachined XY-stage of the scratch-drive actuation mechanism. The lens scanner is placed at the focal length from an incident optical fiber to collimate the transmitting light. The collimated beam is steered two-dimensionally by the XY -motion of the microlens with respect to the incident fiber. We also have developed a theoretical model to predict appropriate initial resist thickness and diameter for the scanning lens. An optical scanning angle of ±7° has been demonstrated by sliding a microlens of 670-µm focal length at a physical stroke of ±67 µm. Typical angular positioning resolution has been estimated to be 0.018°. |
BibTeX:
@article{toshiyoshi_surface_2003,
author = {Toshiyoshi, Hiroshi and Su, Guo-Dung John and LaCosse, Jason and Wu, Ming C.},
title = {A Surface Micromachined Optical Scanner ArrayUsing Photoresist Lenses Fabricated by aThermal Reflow Process},
journal = {Journal of Lightwave Technology},
year = {2003},
volume = {21},
number = {7},
pages = {1700},
url = {http://jlt.osa.org/abstract.cfm?URI=jlt-21-7-1700}
}
|
| Islam MS, Jung T, Itoh T, Wu MC, Nespola A, Sivco DL and Cho AY (2002), "High Power and Highly Linear Monolithically Integrated Distributed Balanced Photodetectors", Journal of Lightwave Technology., February, 2002. Vol. 20(2), pp. 285. |
| Abstract: A distributed balanced photodetector with high saturation photocurrent and excellent linearity has been experimentally demonstrated. The maximum linear direct current (dc) photocurrent of 33 mA per branch is equivalent to 66mA in single-ended photodetectors. A setup for investigating the alternating current (ac) linearity of the receiver is proposed and experimentally demonstrated. The receiver exhibits high ac linearity, even under high power operation. The bandwidth of the receiver remains unchanged when the effective dc photocurrent is varied from 1 mA to 21 mA. The distribution of photocurrents was also measured. Device length for optimum radiofrequency (RF) performance is calculated and implemented in the design. A correlation between the dark current of the photodiodes and their failure mechanism has been established. Analyzing the failure mechanism,junction diodes are found to be more suitable for high power applications. |
BibTeX:
@article{islam_high_2002,
author = {Islam, M. Saif and Jung, Thomas and Itoh, Tatsuo and Wu, Ming C. and Nespola, Antonino and Sivco, Deborah L. and Cho, Alfred Y.},
title = {High Power and Highly Linear Monolithically Integrated Distributed Balanced Photodetectors},
journal = {Journal of Lightwave Technology},
year = {2002},
volume = {20},
number = {2},
pages = {285},
url = {http://jlt.osa.org/abstract.cfm?URI=jlt-20-2-285}
}
|
| Murthy S, Wu MC, Sivco D and Cho AY (2002), "Parallel feed travelling wave distributed pin photodetectors with integrated MMI couplers", Electronics Letters. Vol. 38(2), pp. 78-80. |
| Abstract: The fabrication and performance of a parallel feed travelling wave photodetector with pin diodes operating at 1550 nm is presented. A parallel optical feed using an integrated multimode interference (MMI) power splitter helps increase the maximum linear photocurrent through a more uniform distribution of photocurrent. The maximum DC linear current measured is 52.2 mA. Maximum linear RF power at 10 GHz was 9 dBm. (9 References). |
BibTeX:
@article{murthy_parallel_2002,
author = {Murthy, S. and Wu, M. C. and Sivco, D. and Cho, A. Y.},
title = {Parallel feed travelling wave distributed pin photodetectors with integrated MMI couplers},
journal = {Electronics Letters},
year = {2002},
volume = {38},
number = {2},
pages = {78--80},
url = {file:///C:/Program%20Files/EndNote%208/Libraries/Publications.Data/Murthy%20-%20Parallel%20feed%20traveling%20wave%20distributed%20pin%20photodetectors%20w%20integrated%20MMI%20couplers.pdf}
}
|
| Murthy S, Jung T, Wu M, Sivco D and Cho A (2002), "Travelling wave distributed photodetectors with backward wave cancellation for improved AC efficiency", Electronics Letters., July, 2002. Vol. 38(15), pp. 827-829. |
| Abstract: In travelling wave distributed photodetectors, half the photocurrent generated in each individual photodiode is lost in the input termination. Here, a multi-section transmission line for cancellation of the backward travelling wave to achieve up to 6 dB improvement in the RF magnitude response without any bandwidth reduction is proposed and demonstrated |
BibTeX:
@article{murthy_travelling_2002,
author = {Murthy, S. and Jung, T. and Wu, M.C. and Sivco, D.L. and Cho, AY.},
title = {Travelling wave distributed photodetectors with backward wave cancellation for improved AC efficiency},
journal = {Electronics Letters},
year = {2002},
volume = {38},
number = {15},
pages = {827--829},
doi = {10.1049/el:20020532}
}
|
| Paik J-A, Fan S-K, Kim C-J, Wu MC and Dunn B (2002), "Micromachining of mesoporous oxide films for microelectromechanical system structures", Journal of Materials Research. Vol. 17(08), pp. 2121-2129. |
| Abstract: The high porosity and uniform pore size of mesoporous oxide films offer unique opportunities for microelectromechanical system (MEMS) devices that require low density and low thermal conductivity. This paper provides the first report in which mesoporous films were adapted for MEMS applications. Mesoporous SiO2 and Al2O3 films were prepared by spin coating using block copolymers as the structure-directing agents. The resulting films were over 50% porous with uniform pores of 8-nm average diameter and an extremely smooth surface. The photopatterning and etching characteristics of the mesoporous films were investigated and processing protocols were established which enabled the films to serve as the sacrificial layer or the structure layer in MEMS devices. The unique mesoporous morphology leads to novel behavior including extremely high etching rates and the ability to etch underlying layers. Surface micromachining methods were used to fabricate three basic MEMS structures, microbridges, cantilevers, and membranes, from the mesoporous oxides. |
BibTeX:
@article{paik_micromachining_2002,
author = {Paik, Jong-Ah and Fan, Shih-Kang and Kim, Chang-Jin and Wu, Ming C. and Dunn, Bruce},
title = {Micromachining of mesoporous oxide films for microelectromechanical system structures},
journal = {Journal of Materials Research},
year = {2002},
volume = {17},
number = {08},
pages = {2121--2129},
doi = {10.1557/JMR.2002.0313}
}
|
| Islam M, Murthy S, Itoh T, Wu M, Novak D, Waterhouse R, Sivco DL and Cho AY (2001), "Velocity-matched distributed photodetectors and balanced photodetectors with p-i-n photodiodes", IEEE Transactions on Microwave Theory and Techniques., October, 2001. Vol. 49(10), pp. 1914-1920. |
| Abstract: We report on the first demonstration of velocity-matched distributed photodetectors and balanced photodetectors with p-i-n photodetectors. Record-high linear dc photocurrent of 45 mA has been achieved without suffering from thermal damage, thanks to the superior power handling capability of p-i-n photodiodes. A novel fiber alignment technique has been developed to achieve high linear photocurrent. More than 37 dB of common-mode-rejection ratio and 45-dB suppression of laser relative intensity noise over a broad frequency range have been achieved using the distributed balanced photodetectors in an RF fiber-optic link. The frequency response is flat from 1 to 35 GHz |
BibTeX:
@article{islam_velocity-matched_2001,
author = {Islam, M.S. and Murthy, S. and Itoh, T. and Wu, M.C. and Novak, D. and Waterhouse, R.B. and Sivco, Deborah L. and Cho, Alfred Y.},
title = {Velocity-matched distributed photodetectors and balanced photodetectors with p-i-n photodiodes},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {2001},
volume = {49},
number = {10},
pages = {1914--1920},
doi = {10.1109/22.954807}
}
|
| Mathai S, Cappelluti F, Jung T, Novak D, Waterhouse R, Sivco D, Cho AY, Ghione G and Wu M (2001), "Experimental demonstration of a balanced electroabsorption modulated microwave photonic link", IEEE Transactions on Microwave Theory and Techniques., October, 2001. Vol. 49(10), pp. 1956-1961. |
| Abstract: A novel balanced electroabsorption modulated photonic link for simultaneous suppression of even-order distortions, third-order distortions, laser relative intensity noise (RIN), and common amplified spontaneous emission noise at the same modulator bias point was experimentally demonstrated for the first time. By biasing the balanced electroabsorption modulator at the third-order null, the third-order distortions were suppressed, while the balanced link architecture suppressed all even-order distortions and common mode noises. The fabricated balanced electroabsorption modulator (B-EAM) showed well-matched dc characteristics in terms of I-V and transfer curve. System experiments were performed to compare single-EAM and B-EAM links. In the B-EAM link, 2-dB suppression of laser RIN and 20-dB improvement in spurious free dynamic range over the single-EAM link were observed |
BibTeX:
@article{mathai_experimental_2001,
author = {Mathai, S. and Cappelluti, F. and Jung, T. and Novak, D. and Waterhouse, R.B. and Sivco, Deborah and Cho, Alfred Y. and Ghione, G. and Wu, M.C.},
title = {Experimental demonstration of a balanced electroabsorption modulated microwave photonic link},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {2001},
volume = {49},
number = {10},
pages = {1956--1961},
doi = {10.1109/22.954814}
}
|
| Narasimha A, Meng X, Lam CF, Wu MC and Yablonovitch E (2001), "Maximizing spectral utilization in WDM systems by microwave domain filtering of tandem single sidebands", IEEE Transactions on Microwave Theory and Techniques. Vol. 49(10), pp. 2042–2047. |
BibTeX:
@article{narasimha_maximizing_2001,
author = {Narasimha, Adithyaram and Meng, Xuejun and Lam, Cedric F. and Wu, Ming C. and Yablonovitch, Eli},
title = {Maximizing spectral utilization in WDM systems by microwave domain filtering of tandem single sidebands},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {2001},
volume = {49},
number = {10},
pages = {2042–2047},
url = {http://nanophotonics.eecs.berkeley.edu/pdf/Narasimha%20-%20Maximizing%20Spectral%20Utilization%20in%20WDM%20Systems%20by%20Microwave%20Domain%20Filtering%20of%20Tandem%20Single%20Sidebands.pdf}
}
|
| Shen JL, Chang CY, Chen PN, Chou WC, Chen YF and Wu MC (2001), "Optical absorption studies in absorbing Bragg reflectors", Optics Communications., November, 2001. Vol. 199(1–4), pp. 155-159. |
| Abstract: Reflectivity and photoluminescence have been used to study optical absorption from an absorbing Bragg reflector consisting of AlAs/GaAs Bragg reflector and InGaAs/InGaAsP multiple-quantum-well absorbing layer. An absorption dip due to the optical confinement of the Fabry–Perot resonance was observed in the reflectivity spectrum. Based on the transfer matrix method along with the complex index of refraction, we successfully analyzed the reflectivity spectrum and obtained the absorption coefficient of the absorbing cavity around 1550 nm. We also demonstrated that the quality factor of the Fabry–Perot mode in photoluminescence could be used to estimate the absorption coefficient of the cavity medium in our absorbing Bragg reflector. |
BibTeX:
@article{shen_optical_2001,
author = {Shen, J. L and Chang, C. Y and Chen, P. N and Chou, W. C and Chen, Y. F and Wu, M. C},
title = {Optical absorption studies in absorbing Bragg reflectors},
journal = {Optics Communications},
year = {2001},
volume = {199},
number = {1–4},
pages = {155--159},
url = {http://www.sciencedirect.com/science/article/pii/S0030401801015899},
doi = {10.1016/S0030-4018(01)01589-9}
}
|
| Su G-D, Toshiyoshi H and Wu M (2001), "Surface-micromachined 2-D optical scanners with high-performance single-crystalline silicon micromirrors", IEEE Photonics Technology Letters., June, 2001. Vol. 13(6), pp. 606-608. |
| Abstract: We have developed a novel batch-fabrication single-crystalline silicon micromirror bonding process to fabricate optically flat micromirrors on polysilicon surface-micromachined two-dimensional (2-D) scanners. The electrostatically actuated 2-D scanner has a mirror area of 460 /spl mu/m/spl times/460 /spl mu/m and an optical scan angle of /spl plusmn/7.5/spl deg/. Compared with micromirror made by standard polysilicon surface-micromachining process, the radius of curvature of the micromirror has been improved by 150 times from 1.8 to 265 cm, with surface roughness textless10 nm. |
BibTeX:
@article{su_surface-micromachined_2001,
author = {Su, G.-D.J. and Toshiyoshi, H. and Wu, M.C.},
title = {Surface-micromachined 2-D optical scanners with high-performance single-crystalline silicon micromirrors},
journal = {IEEE Photonics Technology Letters},
year = {2001},
volume = {13},
number = {6},
pages = {606--608},
doi = {10.1109/68.924038}
}
|
| Toshiyoshi H, Piyawattanametha W, Chan C-T and Wu M (2001), "Linearization of electrostatically actuated surface micromachined 2-D optical scanner", Journal of Microelectromechanical Systems., June, 2001. Vol. 10(2), pp. 205-214. |
| Abstract: This paper presents an effective method of linearizing the electrostatic transfer characteristics of micromachined two-dimensional (2-D) scanners. The orthogonal scan angles of surface micromachined polysilicon scanner are controlled by using quadrant electrodes for electrostatic actuation. By using a pair of differential voltages over a bias voltage, we could improve the distortion of projected images from 72% to only 13 A theoretical model has been developed to predict the angle-voltage transfer characteristics of the 2-D scanner. The simulation results agree very well with experimental data. Differential voltage operation has been found to suppress the crosstalk of two orthogonal scan axes by both experiment and theoretically. We have found that a circular mirror is expected to have the lowest angular distortion compared with square mirrors. Perfect grid scanning pattern of small distortion (0.33 has been successfully obtained by predistorting the driving voltages after calibration |
BibTeX:
@article{toshiyoshi_linearization_2001,
author = {Toshiyoshi, H. and Piyawattanametha, W. and Chan, Cheng-Ta and Wu, M.C.},
title = {Linearization of electrostatically actuated surface micromachined 2-D optical scanner},
journal = {Journal of Microelectromechanical Systems},
year = {2001},
volume = {10},
number = {2},
pages = {205--214},
doi = {10.1109/84.925744}
}
|
| Wang W, Davis R, Jung T, Lodenkamper R, Lembo L, Brock J and Wu M (2001), "Characterization of a coherent optical RF channelizer based on a diffraction grating", IEEE Transactions on Microwave Theory and Techniques., October, 2001. Vol. 49(10), pp. 1996-2001. |
| Abstract: A coherent optical RF channelizer has been constructed and characterized. The optical channelizer is based on a free-space optical diffraction grating, and utilizes coherent optical heterodyne detection to translate all of the frequency channels to a common intermediate frequency (IF). The designed optical channelizer has a 1-GHz channel spacing, and a nominal 5-GHz IF and can offer an instantaneous bandwidth greater than 100 GHz. The channelizing receiver has been characterized for its frequency response, crosstalk, and spur-free dynamic range, and the results are in a good agreement with the theoretical values |
BibTeX:
@article{wang_characterization_2001,
author = {Wang, Wenshen and Davis, R.L. and Jung, T.J. and Lodenkamper, R. and Lembo, L.J. and Brock, J.C. and Wu, M.C.},
title = {Characterization of a coherent optical RF channelizer based on a diffraction grating},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {2001},
volume = {49},
number = {10},
pages = {1996--2001},
doi = {10.1109/22.954820}
}
|
| Chau T, Kaneda N, Jung T, Rollinger A, Mathai S, Qian Y, Itoh T, Wu MC, Shillue WP and Payne JM (2000), "Generation of millimeter waves by photomixing at 1.55 mm using InGaAs-InAlAs-InP velocity-matched distributed photodetectors", IEEE Photon. Technol. Lett. Vol. 12(8), pp. 1055–1057. |
BibTeX:
@article{chau_generation_2000,
author = {Chau, T. and Kaneda, N. and Jung, T. and Rollinger, A. and Mathai, S. and Qian, Y. and Itoh, T. and Wu, M. C. and Shillue, W. P. and Payne, J. M.},
title = {Generation of millimeter waves by photomixing at 1.55 mm using InGaAs-InAlAs-InP velocity-matched distributed photodetectors},
journal = {IEEE Photon. Technol. Lett},
year = {2000},
volume = {12},
number = {8},
pages = {1055–1057},
url = {http://nanophotonics.eecs.berkeley.edu/pdf/Chau%20-%20Generation%20of%20millimeter%20waves%20by%20photomixing....pdf}
}
|
| Murthy S, Jung T, Chau T, Wu MC, Sivco DL and Cho AY (2000), "A novel monolithic distributed traveling-wave photodetector with parallel optical feed", IEEE Photonics Technology Letters. Vol. 12(6), pp. 681-3. |
| Abstract: We report on a novel monolithic distributed traveling wave photodetector with parallel optical feed to an array of individual photodiodes using an integrated multimode interference (MMI) coupler to attain high saturation current. The parallel optical feed reduces the maximum photocurrent and photocurrent density seen by any single photodiode, thus increasing the maximum linear photocurrent of the detector. We have successfully fabricated a device with a maximum linear photocurrent of 20 mA and a responsivity of 0.13 A/W. (12 References). |
BibTeX:
@article{murthy_novel_2000,
author = {Murthy, S. and Jung, T. and Chau, Tai and Wu, M. C. and Sivco, D. L. and Cho, A. Y.},
title = {A novel monolithic distributed traveling-wave photodetector with parallel optical feed},
journal = {IEEE Photonics Technology Letters},
year = {2000},
volume = {12},
number = {6},
pages = {681--3},
url = {file:///C:/Program%20Files/EndNote%208/Libraries/Publications.Data/Murthy%20-%20A%20Novel%20Monolithic%20Distributed%20Traveling-Wave%20Photodetector%20w%20Parallel%20Optical%20Feed.pdf}
}
|
| Narasimha A, Meng X, Wu M and Yablonovitch E (2000), "Tandem single sideband modulation scheme for doubling spectral efficiency of analogue fibre links", Electronics Letters., June, 2000. Vol. 36(13), pp. 1135-1136. |
| Abstract: Using a dual-electrode Mach-Zehnder modulator, a `tandem' single sideband modulator has been constructed that doubles the spectral efficiency of a system by enabling the transmission of different data streams in the upper and lower sidebands of the same optical carrier |
BibTeX:
@article{narasimha_tandem_2000,
author = {Narasimha, A and Meng, X.J. and Wu, M.C. and Yablonovitch, E.},
title = {Tandem single sideband modulation scheme for doubling spectral efficiency of analogue fibre links},
journal = {Electronics Letters},
year = {2000},
volume = {36},
number = {13},
pages = {1135--1136},
doi = {10.1049/el:20000836}
}
|
| SAIF ISLAM M, CHAU T, ITOH T, WU MC, SIVCO DL and CHO AY (2000), "DISTRIBUTED BALANCED PHOTODETECTOR FOR RF PHOTONIC APPLICATIONS", International Journal of High Speed Electronics and Systems., March, 2000. Vol. 10(01), pp. 281-297. |
| Abstract: A novel velocity-matched distributed balanced photodetector operating at 1.3 and 1.55 μm wavelengths has been proposed and experimentally demonstrated. Distributed absorption and velocity matching of the optical and microwave signals are employed to achieve high saturation photocurrent. The velocity matching between the incident optical wave and the output microwave signal allows the detector length and effective absorption volume to increase without penalizing the bandwidth. A common-mode rejection ratio greater than 27 dB has been achieved over a wide range of photocurrents. More than 24-dB suppression of the relative intensity noise of the laser source and EDFA added noise has been achieved in a broadband RF link experiment. Shot-noise limited performance has been achieved with significant improvements in the signal-to-noise ratio over a wide range of frequencies and phase mismatch of input RF signals. The experimental results indicate that the distributed balanced photodetector will have a major impact on most RF photonic systems with its superior potential of reaching very high power levels. |
BibTeX:
@article{saif_islam_distributed_2000,
author = {SAIF ISLAM, M. and CHAU, TAI and ITOH, TATSUO and WU, MING C. and SIVCO, DEBORAH L. and CHO, ALFRED Y.},
title = {DISTRIBUTED BALANCED PHOTODETECTOR FOR RF PHOTONIC APPLICATIONS},
journal = {International Journal of High Speed Electronics and Systems},
year = {2000},
volume = {10},
number = {01},
pages = {281--297},
url = {http://www.worldscientific.com/doi/abs/10.1142/S0129156400000313},
doi = {10.1142/S0129156400000313}
}
|
| Wu MC, Fan L and Su G-D (2000), "Micromechanical Photonic Integrated Circuits", IEICE TRANSACTIONS on Electronics., June, 2000. Vol. E83-C(6), pp. 903-911. |
| Abstract: We report on a novel micromechanical photonic integrated circuits (PIC) for integrating free-space optical systems on a chip. Using polysilicon surface-micromachining technique, micro-optical elements, three-dimensional optomechanical structures, and microactuators are monolithically integrated on silicon substrate. We will discuss the basic building blocks of the micromechanical PIC, including XYZ micropositioners, 2-axis tilting micromirrors, scanning microlenses, and their integration with vertical cavity surface-emitting lasers. We will also discuss their applications in reconfigurable optical interconnect and active alignment in parallel free-space optical interconnect systems. |
BibTeX:
@article{wu_micromechanical_2000,
author = {Wu, Ming C. and Fan, Li and Su, Guo-Dong},
title = {Micromechanical Photonic Integrated Circuits},
journal = {IEICE TRANSACTIONS on Electronics},
year = {2000},
volume = {E83-C},
number = {6},
pages = {903--911},
url = {http://search.ieice.org/bin/summary.php?id=e83-c_6_903&category=C&year=2000&lang=E&abst=}
}
|
| Chen RT, Nguyen H and Wu MC (1999), "A high-speed low-voltage stress-induced micromachined 2*2 optical switch", IEEE Photonics Technology Letters. Vol. 11(11), pp. 1396-8. |
| Abstract: A low-voltage electrostatically actuated 2*2 fiber optic switch is achieved using a stress-induced curved polysilicon actuator. The curved polysilicon beam substantially lowers the electrostatic operating voltage of the switch. Large mirror displacement (300 mu m) and low operating voltage (20 V) are obtained simultaneously. Sub-millisecond switching time ([left angle bracket]600 mu s), low optical insertion loss (0.7 dB), and small polarization-dependent loss (0.09 dB) have been achieved. (8 References). |
BibTeX:
@article{chen_high-speed_1999,
author = {Chen, R. T. and Nguyen, H. and Wu, M. C.},
title = {A high-speed low-voltage stress-induced micromachined 2*2 optical switch},
journal = {IEEE Photonics Technology Letters},
year = {1999},
volume = {11},
number = {11},
pages = {1396--8},
url = {file:///C:/Program%20Files/EndNote%208/Libraries/Publications.Data/Chen%20-%20A%20high-speed%20low-voltage%20stress%20induced%20micromachined%202x2%20switch.pdf}
}
|
| Islam M, Chan T, Nespola A, Mathai S, Rollinger A, Deal W, Itoh T, Wu M, Sivco DL and Cho A (1999), "Distributed balanced photodetectors for high-performance RF photonic links", IEEE Photonics Technology Letters., April, 1999. Vol. 11(4), pp. 457-459. |
| Abstract: A novel velocity-matched distributed balanced photodetector with a 50-/spl Omega/ coplanar waveguide output transmission line has been experimentally demonstrated in the InP-InGaAs material system. Distributed absorption and velocity matching are employed to achieve high-saturation photocurrent. A common mode rejection ratio of 27 dB has been achieved. The RF link experiment conducted at 6.48 GHz shows that the laser intensity noise has been suppressed by more than 17 dB. |
BibTeX:
@article{islam_distributed_1999,
author = {Islam, M.S. and Chan, Tai and Nespola, A and Mathai, S. and Rollinger, AR. and Deal, W.R. and Itoh, T. and Wu, M.C. and Sivco, Deborah L. and Cho, AY.},
title = {Distributed balanced photodetectors for high-performance RF photonic links},
journal = {IEEE Photonics Technology Letters},
year = {1999},
volume = {11},
number = {4},
pages = {457--459},
doi = {10.1109/68.752547}
}
|
| Jung T, Shen J-L, Tong DTK, Murthy S, Wu M, Tanbun-Ek T, Wang W, Lodenkamper R, Davis R, Lembo LJ and Brock JC (1999), "CW injection locking of a mode-locked semiconductor laser as a local oscillator comb for channelizing broad-band RF signals", IEEE Transactions on Microwave Theory and Techniques., July, 1999. Vol. 47(7), pp. 1225-1233. |
| Abstract: CW injection locking of mode-locked semiconductor lasers has been experimentally demonstrated. The phases of the mode-locked frequency comb are shown to be coherent with that of the master CW laser. The pulsewidth of the mode-locked laser remains almost unchanged (textless2 ps) for a broad range of injection power (-28 to -12 dBm). Pulling of the entire mode-locked frequency comb by 400 MHz has been demonstrated. The coherent multifrequency source can be used as a local oscillator comb for coherent optical channelizers for ultrawide-band RF signals |
BibTeX:
@article{jung_cw_1999,
author = {Jung, T. and Shen, Ji-Lin and Tong, D. T K and Murthy, S. and Wu, M.C. and Tanbun-Ek, T. and Wang, Wenshen and Lodenkamper, R. and Davis, R. and Lembo, L. J. and Brock, J. C.},
title = {CW injection locking of a mode-locked semiconductor laser as a local oscillator comb for channelizing broad-band RF signals},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {1999},
volume = {47},
number = {7},
pages = {1225--1233},
doi = {10.1109/22.775461}
}
|
| Lee S-S, Huang L-S, Kim C-J and Wu MC (1999), "Free-space fiber-optic switches based on MEMS vertical torsion mirrors", Journal of Lightwave Technology. Vol. 17(1), pp. 7-13. |
| Abstract: This paper reports on the design, fabrication, and performance of a novel MEMS (micro-electro-mechanical-system) fiber-optic switch based on surface-micromachined vertical torsion mirrors. The vertical torsion mirror itself can be used as a 1*2 or an ON-OFF switch. A 2*2 MEMS fiber-optic switch with four vertical torsion mirrors has also been fabricated. The switching voltage is measured to be 80 V for switching angles of 45 degrees . We have achieved a switching time of less than 400 mu s (fall time) and an optical insertion loss of 1.25 dB for single-mode fibers. In addition, a bulk-micromachined silicon submount has been developed to package the switch with microball lenses and multimode fibers with passive alignment. With the micromachined switch chip and the hybrid-packaging scheme, the size, weight, and potentially the cost of the fiber-optic switches can be dramatically reduced. (14 References). |
BibTeX:
@article{lee_free-space_1999,
author = {Lee, Shi-Sheng and Huang, Long-Sun and Kim, Chang-Jin and Wu, M. C.},
title = {Free-space fiber-optic switches based on MEMS vertical torsion mirrors},
journal = {Journal of Lightwave Technology},
year = {1999},
volume = {17},
number = {1},
pages = {7--13},
url = {file:///C:/Program%20Files/EndNote%208/Libraries/Publications.Data/Lee%20-%20Free-Space%20Fiber-Optic%20Switches%20Based%20on%20MEMS%20Vertical%20Torsion%20Mirrors.pdf}
}
|
| Meng XJ, Chau T and Wu M (1999), "Improved intrinsic dynamic distortions in directly modulated semiconductor lasers by optical injection locking", IEEE Transactions on Microwave Theory and Techniques., July, 1999. Vol. 47(7), pp. 1172-1176. |
| Abstract: The effects of optical injection locking on the nonlinear distortions of directly modulated semiconductor distributed feedback (DFB) lasers are investigated experimentally. The second harmonic distortion (SHD) and third harmonic distortion (THD), as well as the third-order intermodulation distortion (IMD3), are measured as functions of modulation frequency for both the free-running and injection-locked lasers. Under strong injection locking with -8-dB injection ratio, the SHD and THD of the DFB laser have been suppressed by 15 dB from 2 to 4 GHz. Moreover, nearly 15-dB reduction in IMD3 has been observed from 1.4 to 3.0 GHz with the same injection conditions. We also found that the injection locking is not effective in reducing the low-frequency distortions |
BibTeX:
@article{meng_improved_1999,
author = {Meng, Xue Jun and Chau, Tai and Wu, M.C.},
title = {Improved intrinsic dynamic distortions in directly modulated semiconductor lasers by optical injection locking},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {1999},
volume = {47},
number = {7},
pages = {1172--1176},
doi = {10.1109/22.775454}
}
|
| Nespola A, Chau T, Wu M and Ghione G (1999), "Analysis of failure mechanisms in velocity-matched distributed photodetectors", Optoelectronics, IEE Proceedings -., August, 1999. Vol. 146(1), pp. 25-30. |
| Abstract: The thermal-runaway process in long-wavelength velocity-matched distributed photodetectors (VMDP) with metal-semiconductor-metal photodiodes has been investigated. A three-dimensional numerical electrothermal model has been developed which takes into account the nonlinear thermal properties of the substrate and the nonuniform temperature rise due to self heating. The model shows that, owing to its distributed nature, the photodetector is able to operate at high optical power level before catastrophic failure occurs. When this happens, a highly localised hot spot appears within the device and characteristic exhibits a typical current point, where the current rapidly increases with increasing bias voltage. Examples are discussed to highlight the thermal behaviour of the distributed detector and to compare the model with experimental data |
BibTeX:
@article{nespola_analysis_1999,
author = {Nespola, A and Chau, T. and Wu, M.C. and Ghione, G.},
title = {Analysis of failure mechanisms in velocity-matched distributed photodetectors},
journal = {Optoelectronics, IEE Proceedings -},
year = {1999},
volume = {146},
number = {1},
pages = {25--30},
doi = {10.1049/ip-opt:19990457}
}
|
| Saiful Islam M, Chau T, Mathai S, Itoh T, Wu M, Sivco DL and Cho AY (1999), "Distributed balanced photodetectors for broad-band noise suppression", IEEE Transactions on Microwave Theory and Techniques., July, 1999. Vol. 47(7), pp. 1282-1288. |
| Abstract: A novel velocity-matched distributed balanced photodetector with a 50-Ω coplanar waveguide output transmission line has been experimentally demonstrated in the InP/InGaAs material system. Distributed absorption and velocity matching are employed to increase the saturation photocurrent. A common-mode rejection ratio greater than 27 dB has been achieved. The radio-frequency (RF) link experiment conducted at 4.16 GHz shows that the relative intensity noise of the laser has been suppressed by more than 24 dB and shot-noise limited performance has been achieved. Significant improvement of signal-to-noise ratio has been observed over a wide range of frequencies and phase mismatch of input RF signals |
BibTeX:
@article{saiful_islam_distributed_1999,
author = {Saiful Islam, M. and Chau, Tai and Mathai, S. and Itoh, T. and Wu, M.C. and Sivco, Deborah L. and Cho, Alfred Y.},
title = {Distributed balanced photodetectors for broad-band noise suppression},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {1999},
volume = {47},
number = {7},
pages = {1282--1288},
doi = {10.1109/22.775467}
}
|
| Shen JL, Jung T, Murthy S, Chau T, Wu MC, Tong DTK, Lo YH, Chua CL and Zhu ZH (1999), "Mode locking of external-cavity semiconductor lasers with saturable Bragg reflectors", Journal of the Optical Society of America B., July, 1999. Vol. 16(7), pp. 1064-1067. |
| Abstract: We demonstrate the mode locking of external-cavity semiconductor lasers by using a saturable Bragg reflector as an external reflector. Output pulses of 1.9 ps were generated from the semiconductor lasers without dispersion compensation. By coupling the output to a standard single-mode filter with a length of 35 m to compensate for the linear chirp, we have achieved mode-locked pulse durations as short as 880 fs. |
BibTeX:
@article{shen_mode_1999,
author = {Shen, J. L. and Jung, T. and Murthy, S. and Chau, T. and Wu, M. C. and Tong, D. T. K. and Lo, Y. H. and Chua, C. L. and Zhu, Z. H.},
title = {Mode locking of external-cavity semiconductor lasers with saturable Bragg reflectors},
journal = {Journal of the Optical Society of America B},
year = {1999},
volume = {16},
number = {7},
pages = {1064--1067},
url = {http://josab.osa.org/abstract.cfm?URI=josab-16-7-1064},
doi = {10.1364/JOSAB.16.001064}
}
|
| Su G-D, Lee C and Wu M (1999), "Optical scanners realized by surface-micromachined vertical torsion mirror", IEEE Photonics Technology Letters., May, 1999. Vol. 11(5), pp. 587-589. |
| Abstract: We report on a novel vertical torsion mirror fabricated by surface-micromachining for optical scanner applications. Driven by an electrostatic actuator, the scanning mirror has a resonant frequency of 0.5 kHz and an optical scan range of 26/spl deg/. The maximum achievable number of resolvable spots for this 300 /spl mu/m/spl times/250 /spl mu/m scanner is 238. |
BibTeX:
@article{su_optical_1999,
author = {Su, G.-D.J. and Lee, C.D. and Wu, M.C.},
title = {Optical scanners realized by surface-micromachined vertical torsion mirror},
journal = {IEEE Photonics Technology Letters},
year = {1999},
volume = {11},
number = {5},
pages = {587--589},
doi = {10.1109/68.759407}
}
|
| Chan T, Fan L, Tong T, Mathai S, Wu M, Sivco D and Cho A (1998), "Long wavelength velocity-matched distributed photodetectors for RF fibre optic links", Electronics Letters., July, 1998. Vol. 34(14), pp. 1422-1424. |
| Abstract: An InP-based long wavelength velocity-matched distributed photodetector with metal-semiconductor-metal photodiodes is experimentally demonstrated. A 3 dB bandwidth of 18 GHz and an external quantum efficiency of 0.42 A/W have been achieved |
BibTeX:
@article{chan_long_1998,
author = {Chan, T. and Fan, L. and Tong, T.K. and Mathai, S. and Wu, M.C. and Sivco, D.L. and Cho, AY.},
title = {Long wavelength velocity-matched distributed photodetectors for RF fibre optic links},
journal = {Electronics Letters},
year = {1998},
volume = {34},
number = {14},
pages = {1422--1424},
doi = {10.1049/el:19980993}
}
|
| Lam C, Tong DTK, Wu M and Yablonovitvh E (1998), "Experimental demonstration of bipolar optical CDMA system using a balanced transmitter and complementary spectral encoding", IEEE Photonics Technology Letters., October, 1998. Vol. 10(10), pp. 1504-1506. |
| Abstract: We demonstrate a novel balanced differential optical transmitter for spectrally encoded optical code-division multiple-access (CDMA) systems. The proposed structure is suitable for making optical signaling bipolar using complementary spectral encoding. An optical CDMA link with a pair of programmable transmitter and receiver is tested at the OC-3 transmission speed (155 Mb/s) for single-channel transmission. Unmatched code rejection is also demonstrated. |
BibTeX:
@article{lam_experimental_1998,
author = {Lam, C.F. and Tong, D. T K and Wu, M.C. and Yablonovitvh, E.},
title = {Experimental demonstration of bipolar optical CDMA system using a balanced transmitter and complementary spectral encoding},
journal = {IEEE Photonics Technology Letters},
year = {1998},
volume = {10},
number = {10},
pages = {1504--1506},
doi = {10.1109/68.720309}
}
|
| Meng XJ, Tong DTK, Chau T and Wu M (1998), "Demonstration of an analog fiber-optic link employing a directly modulated semiconductor laser with external light injection", IEEE Photonics Technology Letters., November, 1998. Vol. 10(11), pp. 1620-1622. |
| Abstract: We demonstrate an analog fiber-optic link employing a directly modulated semiconductor distributed-feedback (DFB) laser under optical injection locking. The results show that injection locking can significantly improve performances of analog fiber-optic systems at frequencies considerably beyond the bandwidth of free-running semiconductor lasers. |
BibTeX:
@article{meng_demonstration_1998,
author = {Meng, Xue Jun and Tong, D. T K and Chau, Tai and Wu, M.C.},
title = {Demonstration of an analog fiber-optic link employing a directly modulated semiconductor laser with external light injection},
journal = {IEEE Photonics Technology Letters},
year = {1998},
volume = {10},
number = {11},
pages = {1620--1622},
doi = {10.1109/68.726769}
}
|
| Meng XJ, Chau T and Wu M (1998), "Experimental demonstration of modulation bandwidth enhancement in distributed feedback lasers with external light injection", Electronics Letters., October, 1998. Vol. 34(21), pp. 2031-2032. |
| Abstract: The frequency response of a semiconductor distributed feedback (DFB) laser under optical injection locking has been studied experimentally. It is shown that strong injection locking is very effective at increasing the relaxation oscillation frequency of DFB lasers. Bandwidth enhancement as high as 3.7 times has been achieved for the first time |
BibTeX:
@article{meng_experimental_1998,
author = {Meng, Xue Jun and Chau, Tai and Wu, M.C.},
title = {Experimental demonstration of modulation bandwidth enhancement in distributed feedback lasers with external light injection},
journal = {Electronics Letters},
year = {1998},
volume = {34},
number = {21},
pages = {2031--2032},
doi = {10.1049/el:19981434}
}
|
| Meng X, Chau T, Tong D and Wu M (1998), "Suppression of second harmonic distortion in directly modulated distributed feedback lasers by external light injection", Electronics Letters., October, 1998. Vol. 34(21), pp. 2040-2041. |
| Abstract: The suppression of second harmonic distortion in directly modulated semiconductor distributed feedback lasers by optical injection locking has been experimentally demonstrated. Reduction of second harmonic distortion by more than 10 dB has been observed over a wide range of bias currents and modulation frequencies |
BibTeX:
@article{meng_suppression_1998,
author = {Meng, X.J. and Chau, T. and Tong, D.T.K. and Wu, M.C.},
title = {Suppression of second harmonic distortion in directly modulated distributed feedback lasers by external light injection},
journal = {Electronics Letters},
year = {1998},
volume = {34},
number = {21},
pages = {2040--2041},
doi = {10.1049/el:19981415}
}
|
| Tong DTK and Wu M (1998), "Multiwavelength optically controlled phased-array antennas", IEEE Transactions on Microwave Theory and Techniques., January, 1998. Vol. 46(1), pp. 108-115. |
| Abstract: A novel multiwavelength scheme is proposed and demonstrated for one-dimensional (1-D) and two-dimensional (2-D) optically controlled phased-array antenna (OCPAA) systems with true time delay (TTD). This hardware-compressive architecture employs a multiwavelength laser source in conjunction with a programmable dispersion matrix (PDM) and switched optical delay lines (SODLs) to generate all the required time delays for beam steering in 2-D phased-array antenna systems. Independent control of elevation and azimuthal scan is achieved by combining wavelength-dependent and wavelength-independent time delays. An experimental prototype of 4×2 array with 2-b×2-b resolution is constructed to demonstrate the feasibility of the multiwavelength OCPPA (MWOCPAA). Broadband linear RF phase shift is measured in both elevation and azimuthal planes over the entire bandwidth of the electro-optic (EO) modulator. System issues such as insertion loss, array size, and channel isolation are discussed. Extension of the multiwavelength scheme to a common transmit/receive (T/R) module with TTD is also described |
BibTeX:
@article{tong_multiwavelength_1998,
author = {Tong, D. T K and Wu, M.C.},
title = {Multiwavelength optically controlled phased-array antennas},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {1998},
volume = {46},
number = {1},
pages = {108--115},
doi = {10.1109/22.654929}
}
|
| Tong DTK and Wu M (1998), "Transmit/receive module of multiwavelength optically controlled phased-array antennas", IEEE Photonics Technology Letters., July, 1998. Vol. 10(7), pp. 1018-1020. |
| Abstract: We report on a transmit/receive module of multiwavelength optically controlled phased-array antennas. Both transmit and receive mode of the module employs a single programmable dispersion matrix to provide true time delays for all antenna elements. The multiwavelength receiver combines antenna signals in the optical domain without suffering from coherent interference. Therefore, squint-free receiver over a broad frequency band can be achieved. Experimentally, squint-free beam receiving with 2-b scan angle resolution is demonstrated over an equipment-limited frequency range from dc to 4 GHz. |
BibTeX:
@article{tong_transmit/receive_1998,
author = {Tong, D. T K and Wu, M.C.},
title = {Transmit/receive module of multiwavelength optically controlled phased-array antennas},
journal = {IEEE Photonics Technology Letters},
year = {1998},
volume = {10},
number = {7},
pages = {1018--1020},
doi = {10.1109/68.681303}
}
|
| Wu MC, Fan L and Lee S-S (1998), "OPTICAL MEMS: HUGE POSSIBILITIES FOR LILLIPUTIAN-SIZED DEVICES", Optics and Photonics News., June, 1998. Vol. 9(6), pp. 25-29. |
| Abstract: Recent advances in micro-electro-mechanical systems (MEMS) have made it possible to produce entire micro-optical systems in a single chip. After describing this exciting technology, micro-optical benches, XYZ stages, and fiber optic switches are explored. |
BibTeX:
@article{wu_optical_1998,
author = {Wu, Ming C. and Fan, Li and Lee, Shi-Sheng},
title = {OPTICAL MEMS: HUGE POSSIBILITIES FOR LILLIPUTIAN-SIZED DEVICES},
journal = {Optics and Photonics News},
year = {1998},
volume = {9},
number = {6},
pages = {25--29},
url = {http://www.osa-opn.org/abstract.cfm?URI=opn-9-6-25},
doi = {10.1364/OPN.9.6.000025}
}
|
| Fan L, Wu M, Lee HC and Grodzinski P (1997), "Dynamic beam switching of vertical-cavity surface-emitting lasers with integrated optical beam routers", IEEE Photonics Technology Letters., April, 1997. Vol. 9(4), pp. 505-507. |
| Abstract: Dynamic beam switching of vertical-cavity surface-emitting lasers (VCSELs) have been demonstrated for the first time using integrated optical beam routers. The output beam of the VCSEL is switched electrically between two different emission angles. High-speed switching up to 2 GHz has been achieved with an 8 /spl mu/m/spl times/8 /spl mu/m device. Such beam-steering devices are particularly suitable for optical interconnect and photonic switching applications. By integrating the beam routers with VCSELs, the complexity and size of the switching nodes are significantly reduced. |
BibTeX:
@article{fan_dynamic_1997,
author = {Fan, L. and Wu, M.C. and Lee, H. -C and Grodzinski, P.},
title = {Dynamic beam switching of vertical-cavity surface-emitting lasers with integrated optical beam routers},
journal = {IEEE Photonics Technology Letters},
year = {1997},
volume = {9},
number = {4},
pages = {505--507},
doi = {10.1109/68.559403}
}
|
| Lin LY, Wu MC, Itoh T, Vang TA, Muller RE, Sivco DL and Cho AY (1997), "High-power high-speed photodetectors-design, analysis, and experimental demonstration", IEEE Transactions on Microwave Theory & Techniques. Vol. 45(8), pp. 1320-31. |
| Abstract: A novel velocity-matched distributed photodetector (VMDP) is proposed to simultaneously achieve high saturation photocurrent and broad bandwidth. Theoretical analysis on the tradeoff between saturation power and bandwidth shows that the VMDP offers fundamental advantages over conventional photodetectors. A comprehensive theoretical model has been developed for the design and simulation of the VMDP. Experimentally, the VMDP with very high saturation (56-mA) photocurrent and instrument-limited 3-dB bandwidth (49 GHz) has been demonstrated. The theoretical analysis and experimental results show that the VMDP is very attractive for high-performance microwave photonic links and high-power optical microwave applications. (32 References). |
BibTeX:
@article{lin_high-power_1997,
author = {Lin, L. Y. and Wu, M. C. and Itoh, T. and Vang, T. A. and Muller, R. E. and Sivco, D. L. and Cho, A. Y.},
title = {High-power high-speed photodetectors-design, analysis, and experimental demonstration},
journal = {IEEE Transactions on Microwave Theory & Techniques},
year = {1997},
volume = {45},
number = {8},
pages = {1320--31},
url = {file:///C:/Program%20Files/EndNote%208/Libraries/Publications.Data/Lin%20-%20High-power%20high-speed%20photodetectors%20-%20design,%20analysis,%20and%20experimental%20demonstration.pdf}
}
|
| Lin L, Shen J, Lee S and Wu M (1997), "Surface-micromachined micro-XYZ stages for free-space microoptical bench", IEEE Photonics Technology Letters., March, 1997. Vol. 9(3), pp. 345-347. |
| Abstract: Micro-XYZ stages have been monolithically integrated with microactuators and out-of-plane microoptical elements, all fabricated by the same surface-micromachined process, on Si free-space microoptical bench. Optical beam adjustment with three degrees of freedom has been realized without angular squinting. A positioning accuracy of 11 nm has been achieved by the integrated scratch drive actuators, with the travel distance larger than 30 /spl mu/m in each direction. |
BibTeX:
@article{lin_surface-micromachined_1997,
author = {Lin, L.Y. and Shen, J.L. and Lee, S.S. and Wu, M.C.},
title = {Surface-micromachined micro-XYZ stages for free-space microoptical bench},
journal = {IEEE Photonics Technology Letters},
year = {1997},
volume = {9},
number = {3},
pages = {345--347},
doi = {10.1109/68.556068}
}
|
| Motamedi ME, Wu MC and Pister KSJ (1997), "Micro-opto-electro-mechanical devices and on-chip optical processing", Optical Engineering. Vol. 36(5), pp. 1282-97. |
| Abstract: Micro-optical components, such as diffractive and refractive microlenses, micromirrors, beamsplitters, and beam combiners, have recently received considerable attention in the optics R&D centers and finally in the manufacturing community. This achievement is due to micro-electro-mechanical (MEM) technology that has demonstrated major improvements in overall performance and cost of optical systems while offering the possibility of relativity rapid transition to products for military, industrial, and consumer markets. Because of these technology advances, an industrial infrastructure is rapidly becoming established to combine micro-optical components and MEM-based microactuators for on-chip optical processing. Optical systems that once were considered to be impractical due to the limitations of bulk optics can now easily be designed and fabricated with all required optical paths, signal conditioning, and electronic controls integrated on a single chip. On-chip optical processing will enhance the performance of devices such as focal-plane optical concentrators, smart actuators, color separators, beam shapers, fiber data distribution interface (FDDI) switches, digital micromirror devices (DMDs), and miniature optical scanners. We review advances in microoptical components developed at the Rockwell Science Center. We also review the potential of on-chip optical processing and the recent achievement of free-space integrated optics and micro-optical bench components developed at UCLA, and DMDs developed at Texas Instruments. (34 References). |
BibTeX:
@article{motamedi_micro-opto-electro-mechanical_1997,
author = {Motamedi, M. E. and Wu, M. C. and Pister, K. S. J.},
title = {Micro-opto-electro-mechanical devices and on-chip optical processing},
journal = {Optical Engineering},
year = {1997},
volume = {36},
number = {5},
pages = {1282--97}
}
|
| Wu MC, Lin LY, Lee SS and King CR (1997), "Free-Space Integrated Optics Realized by Surface-Micromachining", International Journal of High Speed Electronics and Systems., June, 1997. Vol. 08(02), pp. 283-297. |
| Abstract: A surface-micromachined free-space micro-optical bench (FS-MOB) technology has been proposed to monolithically integrate micro-optical elements, optomechanical structures, micropositioners, and microactuators on the same substrate. Novel three-dimensional micro-optical elements have been fabricated by surface-micromachining techniques. The optical axes of these optical elements are parallel to the substrate, which enables the entire free-space optical system to be integrated on a single substrate. Mocro-scale Fresnel lenses, refractive microlenses, mirrors, beam-splitters, gratings, and precision optical mounts have been successfully fabricated and characterized. Integration of micro-optical elements with translation or rotation stages provides on chip optical alignment or optomechanical switching. This new free-space micro-optical bench technology could significantly reduce the size, weight, an cost of most optical systems, and could have a significant impact on optical switching, optical sensing and optical data storage systems as well as packaging of optoelectronic components. |
BibTeX:
@article{wu_free-space_1997,
author = {Wu, M. C. and Lin, L. Y. and Lee, S. S. and King, C. R.},
title = {Free-Space Integrated Optics Realized by Surface-Micromachining},
journal = {International Journal of High Speed Electronics and Systems},
year = {1997},
volume = {08},
number = {02},
pages = {283--297},
url = {http://www.worldscientific.com/doi/abs/10.1142/S012915649700010X},
doi = {10.1142/S012915649700010X}
}
|
| Wu M (1997), "Micromachining for optical and optoelectronic systems", Proceedings of the IEEE., November, 1997. Vol. 85(11), pp. 1833-1856. |
| Abstract: Micromachining technology opens up many new opportunities for optical and optoelectronic systems. It offers unprecedented capabilities in extending the functionality of optical devices and the miniaturization of optical systems. Movable structures, microactuators, and microoptical elements can be monolithically integrated on the same substrate using batch processing technologies. In this paper, we review the recent advances in this fast-emerging field. The basic bulk- and surface-micromachining technologies applicable to optical systems are reviewed. The free-space microoptical bench and the concept of optical prealignment are introduced. Examples of micromachined optical devices are described, including optical switches with low loss and high contract ratio, low-cost modulators, micromechanical scanners, and the XYZ micropositioners with large travel distance and fine positioning accuracy. Monolithically integrated systems such as single-chip optical disk pickup heads and a femtosecond autocorrelator have also been demonstrated |
BibTeX:
@article{wu_micromachining_1997,
author = {Wu, M.C.},
title = {Micromachining for optical and optoelectronic systems},
journal = {Proceedings of the IEEE},
year = {1997},
volume = {85},
number = {11},
pages = {1833--1856},
doi = {10.1109/5.649660}
}
|
| Chew ST, T.k.tong D, Wu MC and Itoh T (1996), "Optically Assisted Microwave Active Integrated Antennas", IEICE TRANSACTIONS on Electronics., January, 1996. Vol. E79-C(1), pp. 60-67. |
| Abstract: This paper reviews some of the recent effort in the area of microwave-optical interaction as applied to enhance the utility of the active integrated antennas and arrays. The paper consists of two parts. In the first part, the optical bias is used as a hidden port to control the characteristics of the active integrated antennas. Two examples will be presented. In the second part, an optical carrier is used for remoting of active integrated antenna for beam control. |
BibTeX:
@article{chew_optically_1996,
author = {Chew, Siou Teck and T.k.tong, Dennis and Wu, Ming C. and Itoh, Tatsuo},
title = {Optically Assisted Microwave Active Integrated Antennas},
journal = {IEICE TRANSACTIONS on Electronics},
year = {1996},
volume = {E79-C},
number = {1},
pages = {60--67},
url = {http://search.ieice.org/bin/summary.php?id=e79-c_1_60&category=C&year=1996&lang=E&abst=}
}
|
| Chew S-T, Tong DTK, Wu M and Itoh T (1996), "Use of direct-modulated/gain-switched optical links in monopulse-type active phased array systems", IEEE Transactions on Microwave Theory and Techniques., February, 1996. Vol. 44(2), pp. 326-330. |
| Abstract: With the advance of high speed laser technology, optical interaction with microwave circuits has become highly viable. Such interaction is advantageous as the fiber is low-loss, lightweight, and immune to electromagnetic interference. In this paper, interaction of direct-modulated and gain-switched optical links with active antenna phased array systems is demonstrated. In the direct-modulated optical system, the RF signal directly modulates the DFB laser. In the gain-switched optical system, the laser is gain-switched to function as a RF frequency doubler. The modulated signal is transmitted via an optical fiber and recovered at the receiving end by a high-speed photodetector. The recovered RF is then injected into the active antenna phased array systems as an injection-locking reference signal. Two active antenna systems are used for this demonstration: beam-switching and Doppler transceiver |
BibTeX:
@article{chew_use_1996,
author = {Chew, Siou-Teck and Tong, D. T K and Wu, M.C. and Itoh, T.},
title = {Use of direct-modulated/gain-switched optical links in monopulse-type active phased array systems},
journal = {IEEE Transactions on Microwave Theory and Techniques},
year = {1996},
volume = {44},
number = {2},
pages = {326--330},
doi = {10.1109/22.481583}
}
|
| King CR, Lin L and Wu M (1996), "Out-of-plane refractive microlens fabricated by surface micromachining", IEEE Photonics Technology Letters., October, 1996. Vol. 8(10), pp. 1349-1351. |
| Abstract: A novel refractive microlens standing perpendicular to the substrate has been fabricated for the first time with surface-micromachining techniques. The microlens has a focal length of 670 /spl mu/m and a diameter of 300 /spl mu/m. The optical axis of the microlens is precisely defined by photolithography and can be pre-aligned to other surface-micromachined micro-optical elements integrated on the same substrate. The focusing and collimating abilities of the lens are successfully demonstrated. The refractive microlens offers higher efficiency compared with diffractive lenses, and is very useful for high-performance free-space micro-optical bench applications. |
BibTeX:
@article{king_out--plane_1996,
author = {King, C. R. and Lin, L.Y. and Wu, M.C.},
title = {Out-of-plane refractive microlens fabricated by surface micromachining},
journal = {IEEE Photonics Technology Letters},
year = {1996},
volume = {8},
number = {10},
pages = {1349--1351},
doi = {10.1109/68.536651}
}
|
| Lin LY, Shen JL, Lee SS and Wu MC (1996), "Realization of novel monolithic free-space optical disk pickup heads by surface micromachining", Optics Letters., January, 1996. Vol. 21(2), pp. 155-157. |
| Abstract: A novel monolithic free-space optical disk pickup head has been fabricated by micromachined micro-optical bench technology. The pickup head contains a self-aligned semiconductor edge-emitting laser, a collimating lens, a beam splitter, two focusing lenses, and two 45° mirrors. All optical components are built monolithically on Si substrates. The 45° mirror directs the optical output beam in the surface-normal direction. This novel design could significantly reduce the size and the weight of the optical pickup head as well as the cost of the assembly processes. The weight reduction could also greatly increase the data access rate. |
BibTeX:
@article{lin_realization_1996,
author = {Lin, L. Y. and Shen, J. L. and Lee, S. S. and Wu, M. C.},
title = {Realization of novel monolithic free-space optical disk pickup heads by surface micromachining},
journal = {Optics Letters},
year = {1996},
volume = {21},
number = {2},
pages = {155--157},
url = {http://ol.osa.org/abstract.cfm?URI=ol-21-2-155},
doi = {10.1364/OL.21.000155}
}
|
| Lin L, Shen J, Lee S, Wu M and Sergent A (1996), "Tunable three-dimensional solid Fabry-Perot etalons fabricated by surface-micromachining", IEEE Photonics Technology Letters., January, 1996. Vol. 8(1), pp. 101-103. |
| Abstract: We report on novel tunable three-dimensional solid Fabry-Perot etalons fabricated by the surface-micromachining technique. The Fabry-Perot etalon is monolithically integrated with an on-chip rotation stage for angle tuning. A wavelength tuning range of 45 nm has been achieved at 1.3 /spl mu/m wavelength for a rotation angle of 70/spl deg/. The optical properties of the polysilicon materials have also been characterized using the etalon as testing vehicles. |
BibTeX:
@article{lin_tunable_1996,
author = {Lin, L.Y. and Shen, J.L. and Lee, S.S. and Wu, M.C. and Sergent, AM.},
title = {Tunable three-dimensional solid Fabry-Perot etalons fabricated by surface-micromachining},
journal = {IEEE Photonics Technology Letters},
year = {1996},
volume = {8},
number = {1},
pages = {101--103},
doi = {10.1109/68.475792}
}
|
| Lin L, Wu M, Itoh T, Vang T, Muller R, Sivco D and Cho A (1996), "Velocity-matched distributed photodetectors with high-saturation power and large bandwidth", IEEE Photonics Technology Letters., October, 1996. Vol. 8(10), pp. 1376-1378. |
| Abstract: A high-power, high-bandwidth photodetector is experimentally demonstrated using a novel velocity-matched distributed photodetector (VMDP). The distributed photodetector structure can achieve large absorption volume and high-saturation power while maintaining the high-speed performance of the fast photodiodes. The VMDP with 56 mA saturation photocurrent and an instrument-limited 3-dB bandwidth of 49 GHz is achieved. The results show that VMDP is ideal for high-performance microwave fiber-optic links and high-power optical-microwave applications. |
BibTeX:
@article{lin_velocity-matched_1996,
author = {Lin, L.Y. and Wu, M.C. and Itoh, T. and Vang, T.A and Muller, R.E. and Sivco, D.L. and Cho, AY.},
title = {Velocity-matched distributed photodetectors with high-saturation power and large bandwidth},
journal = {IEEE Photonics Technology Letters},
year = {1996},
volume = {8},
number = {10},
pages = {1376--1378},
doi = {10.1109/68.536660}
}
|
| Tong T and Wu M (1996), "Continuously tunable optoelectronic millimetre-wave transmitter using monolithic mode-locked semiconductor laser", Electronics Letters., October, 1996. Vol. 32(21), pp. 2006-2007. |
| Abstract: The authors demonstrate a continuously tunable optoelectronic transmitter which uses a monolithic mode-locked semiconductor laser. Millimetre-wave subcarrier frequencies up to 300 GHz can be generated by photomixing a microwave subcarrier frequency with the selected harmonics of the mode-locked frequency, using an electro-optic modulator. A subcarrier frequency which can be tuned continuously from DC to 43 GHz is achieved experimentally |
BibTeX:
@article{tong_continuously_1996,
author = {Tong, T.K. and Wu, M.C.},
title = {Continuously tunable optoelectronic millimetre-wave transmitter using monolithic mode-locked semiconductor laser},
journal = {Electronics Letters},
year = {1996},
volume = {32},
number = {21},
pages = {2006--2007},
doi = {10.1049/el:19961348}
}
|
| Tong DTK and Wu M (1996), "A novel multiwavelength optically controlled phased array antenna with a programmable dispersion matrix", IEEE Photonics Technology Letters., June, 1996. Vol. 8(6), pp. 812-814. |
| Abstract: We propose and demonstrate a "programmable-dispersion" matrix (PDM) for a novel multiwavelength optically controlled phased array antenna (MWOCPAA). The PDM, when employed in conjunction with a multiwavelength source, generates all the time delays for the entire array. In this multiwavelength control scheme, an optical wavelength-to-array element correspondence is established and there is no splitting loss associated with signal distribution to array elements. The time delays are controlled by the dispersion of the PDM which can be programmed by optical switches. Experimental results demonstrating the feasibility of the MWOCPAA are presented. Broadband linear RF phase shift is measured among various wavelength channels. |
BibTeX:
@article{tong_novel_1996,
author = {Tong, D. T K and Wu, M.C.},
title = {A novel multiwavelength optically controlled phased array antenna with a programmable dispersion matrix},
journal = {IEEE Photonics Technology Letters},
year = {1996},
volume = {8},
number = {6},
pages = {812--814},
doi = {10.1109/68.502103}
}
|
| Tong D and Wu M (1996), "Programmable dispersion matrix using Bragg fibre grating for optically controlled phased array antennas", Electronics Letters., August, 1996. Vol. 32(17), pp. 1532-1533. |
| Abstract: A programmable dispersion matrix implemented with Bragg fibre gratings is demonstrated in conjunction with a multiwavelength laser source for use in optically controlled phased array antennas. Relative time delays are experimentally measured using a prototype programmable dispersion matrix with 2 bit resolution and the results agree well with the theoretical prediction |
BibTeX:
@article{tong_programmable_1996,
author = {Tong, D.T.K. and Wu, M.C.},
title = {Programmable dispersion matrix using Bragg fibre grating for optically controlled phased array antennas},
journal = {Electronics Letters},
year = {1996},
volume = {32},
number = {17},
pages = {1532--1533},
doi = {10.1049/el:19961042}
}
|
| Wu M, Lin L, Lee S and King C (1996), "Integrated devices make an optical bench on a chip", Laser Focus World., February, 1996. Vol. 32(2), pp. 64-68. |
BibTeX:
@article{wu_integrated_1996,
author = {Wu, M.C. and Lin, L.Y. and Lee, S.S. and King, C.R.},
title = {Integrated devices make an optical bench on a chip},
journal = {Laser Focus World},
year = {1996},
volume = {32},
number = {2},
pages = {64--68},
url = {http://www.laserfocusworld.com/content/lfw/en/articles/print/volume-32/issue-2/world-news/integrated-devices-make-an-optical-bench-on-a-chip.html http://www.laserfocusworld.com/content/lfw/en/articles/print/volume-32/issue-2/world-news/integrated-devices-make-an-optical-bench-on-a-chip.html}
}
|
| Fan L, Wu M, Lee HC and Grodzinski P (1995), "Novel vertical-cavity surface-emitting lasers with integrated optical beam router", Electronics Letters., April, 1995. Vol. 31(9), pp. 729-730. |
| Abstract: A novel vertical-cavity surface-emitting laser (VCSEL) with integrated optical beam router is reported. The output beam of the VCSEL has been steered by as much as 9.6° away from the surface-normal direction. Integration of the beam routers with VCSELs significantly reduces the complexity and size of the switching nodes. This device is useful for ultra-dense optical interconnects in massively parallel computers |
BibTeX:
@article{fan_novel_1995,
author = {Fan, L. and Wu, M.C. and Lee, H. -C and Grodzinski, P.},
title = {Novel vertical-cavity surface-emitting lasers with integrated optical beam router},
journal = {Electronics Letters},
year = {1995},
volume = {31},
number = {9},
pages = {729--730},
doi = {10.1049/el:19950514}
}
|
| Fetterman H, Chang Y, Scott D, Forrest S, Espiau FM, Wu M, Plant D, Kelly J, Mather A, Steier W, Osgood R.M. J, Haus H and Simonis G (1995), "Optically controlled phased array radar receiver using SLM switched real time delays", IEEE Microwave and Guided Wave Letters., November, 1995. Vol. 5(11), pp. 414-416. |
| Abstract: We report the results of a demonstration of a real time delay, optically controlled phased array radar receiver. This implementation employed a free space configuration based upon an optical switching network using liquid crystal spatial light modulators (SLM's). A three-delay unit, two-antenna array receiver was implemented at an optical wavelength of 1.3 μm and demonstrated “squint-free” operation over the entire X-band (8-12 GHz) with an angular accuracy of 1.4°. Finally, a novel configuration for the two-antenna element SLM architecture was proposed and demonstrated equivalent system performance with a reduction in the number of components |
BibTeX:
@article{fetterman_optically_1995,
author = {Fetterman, H.R. and Chang, Y. and Scott, D.C. and Forrest, S.R. and Espiau, F. M. and Wu, M. and Plant, D.V. and Kelly, J.R. and Mather, A and Steier, W.H. and Osgood, R.M., Jr. and Haus, H.A and Simonis, G.J.},
title = {Optically controlled phased array radar receiver using SLM switched real time delays},
journal = {IEEE Microwave and Guided Wave Letters},
year = {1995},
volume = {5},
number = {11},
pages = {414--416},
doi = {10.1109/75.473524}
}
|
| Lee S, Lin L, Pister K, Wu M, Lee HC and Grodzinski P (1995), "Passively aligned hybrid integration of 8 x 1 micromachined micro-Fresnel lens arrays and 8 x 1 vertical-cavity surface-emitting laser arrays for free-space optical interconnect", IEEE Photonics Technology Letters., September, 1995. Vol. 7(9), pp. 1031-1033. |
| Abstract: Surface micromachining technique has been successfully applied to the fabrications of a three-dimensional 8/spl times/1 micro-Fresnel lens array and other novel three-dimensional alignment structures. With the help of these three-dimensional structures, self-aligned integration of the micro-Fresnel lens array and an 8/spl times/1 vertical-cavity surface-emitting laser (VCSEL) array is realized for the first time with passive alignment. Individual addressing of the VCSEL/micro-lens element is also successfully demonstrated. With their three-dimensional and array structural characteristics, they are very attractive for free-space optical interconnect and other integrated micro-optical systems.textlesstextgreater |
BibTeX:
@article{lee_passively_1995,
author = {Lee, S.S. and Lin, L.Y. and Pister, K.S.J. and Wu, M.C. and Lee, H. -C and Grodzinski, P.},
title = {Passively aligned hybrid integration of 8 x 1 micromachined micro-Fresnel lens arrays and 8 x 1 vertical-cavity surface-emitting laser arrays for free-space optical interconnect},
journal = {IEEE Photonics Technology Letters},
year = {1995},
volume = {7},
number = {9},
pages = {1031--1033},
doi = {10.1109/68.414692}
}
|
| Lee SS, Lin LY and Wu MC (1995), "Surface‐micromachined free‐space micro‐optical systems containing three‐dimensional microgratings", Applied Physics Letters., October, 1995. Vol. 67(15), pp. 2135-2137. |
| Abstract: Free‐space micro‐optical systems on a chip containing three‐dimensional microgratings have been demonstrated using surface‐micromachining technique. The micrograting is integrated with a rotary stage, a collimating micro‐Fresnel lens, and an edge‐emitting laser held by three‐dimensional alignment structures on a single Si substrate. Diffraction patterns for various grating rotation angles are observed. Another optical interconnect module consisting of three cascaded microgratings is also demonstrated. The micrograting is a basic building block for many micro‐optical systems and is very attractive for applications in microspectrometers, free‐space optical interconnect, optoelectronic packaging, and wavelength‐division multiplexed integrated micro‐optical systems. |
BibTeX:
@article{lee_surfacemicromachined_1995,
author = {Lee, S. S. and Lin, L. Y. and Wu, M. C.},
title = {Surface‐micromachined free‐space micro‐optical systems containing three‐dimensional microgratings},
journal = {Applied Physics Letters},
year = {1995},
volume = {67},
number = {15},
pages = {2135--2137},
url = {http://scitation.aip.org/content/aip/journal/apl/67/15/10.1063/1.114744},
doi = {10.1063/1.114744}
}
|
| Lee S, Lin L and Wu M (1995), "Surface-micromachined free-space fibre-optic switches", Electronics Letters., August, 1995. Vol. 31(17), pp. 1481-1482. |
| Abstract: A novel 2≫MULT2 free-space fibre-optic switch has been fabricated using surface-micromachining technology. The switch is monolithically patterned on the Si substrate. With this approach, the switch can be made compact, light weight and low cost. In addition, it is potentially integrable with other micro-optical elements and interface electronics. The switch is attractive for fibre-optic local area network applications |
BibTeX:
@article{lee_surface-micromachined_1995,
author = {Lee, S.S. and Lin, L.Y. and Wu, M.C.},
title = {Surface-micromachined free-space fibre-optic switches},
journal = {Electronics Letters},
year = {1995},
volume = {31},
number = {17},
pages = {1481--1482},
doi = {10.1049/el:19950987}
}
|
| Lin LY, Lee SS, Pister KSJ and Wu MC (1995), "Self‐aligned hybrid integration of semiconductor lasers with micromachined micro‐optics for optoelectronic packaging", Applied Physics Letters., May, 1995. Vol. 66(22), pp. 2946-2948. |
| Abstract: Novel self‐aligned hybrid integration of semiconductor lasers with three‐dimensional micro‐optical components has been demonstrated. The self‐alignment structures are fabricated integrally with other three‐dimensional micro‐optical elements such as micro‐Fresnel lenses,mirrors, and gratings on a single Si chip by surfacemicromachining technology. The Si substrate serves as a free‐space micro‐optical bench for active and passive optoelectronic components. A divergent beam emitted from an edge‐emitting semiconductor laser has been successfully collimated by the integrated micro‐Fresnel lens. The integration scheme offers a new approach for optoelectronic packaging and a new technology platform for integrating complete free‐space micro‐optical system on a single chip. |
BibTeX:
@article{lin_selfaligned_1995,
author = {Lin, L. Y. and Lee, S. S. and Pister, K. S. J. and Wu, M. C.},
title = {Self‐aligned hybrid integration of semiconductor lasers with micromachined micro‐optics for optoelectronic packaging},
journal = {Applied Physics Letters},
year = {1995},
volume = {66},
number = {22},
pages = {2946--2948},
url = {http://scitation.aip.org/content/aip/journal/apl/66/22/10.1063/1.114238},
doi = {10.1063/1.114238}
}
|
| Shen J, Lin L, Lee S, Wu M and Sergent M (1995), "Surface-micromachined tunable three-dimensional solid Fabry-Perot etalons with dielectric coatings", Electronics Letters., December, 1995. Vol. 31(25), pp. 2172-2173. |
| Abstract: Tunable three-dimensional solid Fabry-Perot etalons with multilayer dielectric coatings have been successfully demonstrated. The out-of-plane etalon is monolithically integrated with a rotation stage using the surface-micromachining technique. A wavelength tuning range of 58.5 nm has been achieved at 1.3 μm wavelength using the on-chip rotation stage |
BibTeX:
@article{shen_surface-micromachined_1995,
author = {Shen, J.L. and Lin, L.Y. and Lee, S.S. and Wu, M.C. and Sergent, M.},
title = {Surface-micromachined tunable three-dimensional solid Fabry-Perot etalons with dielectric coatings},
journal = {Electronics Letters},
year = {1995},
volume = {31},
number = {25},
pages = {2172--2173},
doi = {10.1049/el:19951464}
}
|
| Wu MC, Lin LY, Lee SS and Pister KSJ (1995), "Micromachined free-space integrated micro-optics", Sensors and Actuators A: Physical., August, 1995. Vol. 50(1–2), pp. 127-134. |
| Abstract: The surface-micromachining technique has been employed to fabricate novel three-dimensional micro-optical elements for free-space integrated optics. The optical axes of these optical elements are parallel to the substrate, which enables the entire free-space optical system to be integrated on a single substrate. Microscale Fresnel lenses, mirrors, beam splitters, gratings, and precision optical mounts have been successfully fabricated and characterized. In addition, micropositioners such as rotary stages and linear translational stages are monolithically integrated with the optical components using the same surface-micromachining process to provide on-chip optical alignment or optomechanical switching. Self-aligned hybrid integration with semiconductor edge-emitting lasers and vertical cavity surface-emitting lasers are also demonstrated for the first time. This new free-space micro-optical bench (FSMOB) technology could significantly reduce the size, weight, and cost of most optical systems, and could have a significant impact on optical switching, optical sensing and optical data-storage systems as well as on the packaging of optoelectronic components. |
BibTeX:
@article{wu_micromachined_1995,
author = {Wu, M. C. and Lin, L. -Y. and Lee, S. -S. and Pister, K. S. J.},
title = {Micromachined free-space integrated micro-optics},
journal = {Sensors and Actuators A: Physical},
year = {1995},
volume = {50},
number = {1–2},
pages = {127--134},
url = {http://www.sciencedirect.com/science/article/pii/0924424796800963},
doi = {10.1016/0924-4247(96)80096-3}
}
|
| Chew ST, Tong TK, Wu M and Itoh T (1994), "An active phased array with optical input and beam-scanning capability", IEEE Microwave and Guided Wave Letters., October, 1994. Vol. 4(10), pp. 347-349. |
| Abstract: An active antenna array with optical input and beam scanning capability was developed. The phase shift between antenna elements is controlled by means of unilateral injection locking. The reference signal for injection locking is launched into an optical fiber by a multiquantum-well InGaAs-InGaAsP distributed feedback laser. The RF signal is recovered by a photodetector at the other end of the link and fed to the RF circuit. Experimental results are presented and discussed.textlesstextgreater |
BibTeX:
@article{chew_active_1994,
author = {Chew, Siou Teck and Tong, Tak Kit and Wu, M.C. and Itoh, T.},
title = {An active phased array with optical input and beam-scanning capability},
journal = {IEEE Microwave and Guided Wave Letters},
year = {1994},
volume = {4},
number = {10},
pages = {347--349},
doi = {10.1109/75.324712}
}
|
| Fan L, Wu M, Lee H and Grodzinski P (1994), "10.1 nm range continuous wavelength-tunable vertical-cavity surface-emitting lasers", Electronics Letters., August, 1994. Vol. 30(17), pp. 1409-1410. |
| Abstract: A record wide continuous wavelength tuning range of 10.1 μm is demonstrated in vertical-cavity surface-emitting lasers (VCSELs) with monolithically integrated thin-film metal heaters. Single longitudinal mode and single transverse mode are maintained throughout the tuning range. The thin-film heater can stand higher temperatures over a wider tuning range. It is also separated and electrically isolated from the laser, and can be applied to most existing VCSEL structures |
BibTeX:
@article{fan_10.1_1994,
author = {Fan, L. and Wu, M.C. and Lee, H.C. and Grodzinski, P.},
title = {10.1 nm range continuous wavelength-tunable vertical-cavity surface-emitting lasers},
journal = {Electronics Letters},
year = {1994},
volume = {30},
number = {17},
pages = {1409--1410},
doi = {10.1049/el:19940972}
}
|
| Lin L, Lee S, Pister K and Wu M (1994), "Micro-machined three-dimensional micro-optics for integrated free-space optical system", Photonics Technology Letters, IEEE. Vol. 6(12), pp. 1445-1447. |
| Abstract: Novel, integrable three-dimensional micro-optical elements have been realized by surface micromachining technology. Rotatable mirrors, lenses and beam-splitters standing perpendicular to the substrate are demonstrated. The optical elements are precisely held at 90° angle to the substrate by side latches. The Si substrate serves as a “micro-optical bench” on which monolithic micro-optical systems consisting of movable and static micro-mirrors, lenses and other components are constructed. The optical system is pre-aligned by photolithography. This technology offers a new approach to free-space integrated optics and low-cost optical packaging |
BibTeX:
@article{lin_micro-machined_1994,
author = {Lin, L.Y. and Lee, S.S. and Pister, K.S.J. and Wu, M.C.},
title = {Micro-machined three-dimensional micro-optics for integrated free-space optical system},
journal = {Photonics Technology Letters, IEEE},
year = {1994},
volume = {6},
number = {12},
pages = {1445--1447},
doi = {10.1109/68.392216}
}
|
| Lin L, Lee S, Pister K and Wu M (1994), "Three-dimensional micro-Fresnel optical elements fabricated by micromachining technique", Electronics Letters., March, 1994. Vol. 30(5), pp. 448-449. |
| Abstract: The authors report, for the first time, a three-dimensional binary phase micro-Fresnel optical element standing perpendicular to the substrate. The optical element is fabricated by a micromachining technique. The element has a diameter of 650 μm, a focal length of 0.5 mm and an optical axis of 1 mm above the surface of the substrate. Light from an optical fibre is successfully collimated by the micro-optical element, and the beam profile closely approximates a Gaussian shape |
BibTeX:
@article{lin_three-dimensional_1994,
author = {Lin, L.Y. and Lee, S.S. and Pister, K.S.J. and Wu, M.C.},
title = {Three-dimensional micro-Fresnel optical elements fabricated by micromachining technique},
journal = {Electronics Letters},
year = {1994},
volume = {30},
number = {5},
pages = {448--449},
doi = {10.1049/el:19940277}
}
|
| Tsang W, Wu M, Chen Y, Choa FS, Logan R, Chu S-N, Sergent A, Magill P, Reichmann K and Burrus C (1994), "Long-wavelength InGaAsP/InP multiquantum well distributed feedback and distributed Bragg reflector lasers grown by chemical beam epitaxy", IEEE Journal of Quantum Electronics., June, 1994. Vol. 30(6), pp. 1370-1380. |
| Abstract: We demonstrated the successful operation of long-wavelength InGaAsP low threshold-current index-coupled and gain-coupled DFB lasers grown by chemical beam epitaxy (CBE). For index-coupled DFB lasers, buried-heterostructure six-QW DFB lasers (250 μm long and as-cleaved) operated at 1.55 μm with CW threshold currents 10-15 mA and slope efficiencies up to 0.35 mW/mA (both facets). A side-mode suppression ratio (SMSR) as high as 49 dB was obtained. The lasers operated in the same range even at high temperatures (70°C checked). For gain-coupled DFB lasers, gain-coupling is accomplished by using a InGaAsP quaternary grating or quantum-well grating that absorbs the DFB emission. The use of a quantum-well grating, in particular, greatly facilitates the reproducible regrowth (defect-free) over grating and the control of the coupling coefficient. CW threshold currents mere in the range of 10-15 mA for 250-μm and 13-18 mA for 250-μm and 500-μm cavities, respectively. Slope efficiencies were high, 0.4 mW/mA (both facets). SMSR was as high as 52 dB and remained in the same DFB mode with SMSR staying 50 dB throughout the entire current range. Linewidth×power products of 1.9-4.0 mere measured with minimum linewidths of 1.8-2.2 MHz. No detectable chirp was measured under 2.5 Gb/s modulation. Unlike index-coupled DFB lasers in which mode partition events decrease slowly even when biased above threshold, these lasers have mode partition events shut off sharply as bias approaches threshold (≳0.95 Ith). A very small dispersion penalty of 1.0 dB was measured at 10-11 BER in transmission experiments using these lasers as sources at 1.7 Gb/s over an amplified fiber system of 230 km. No self-pulsation was observed in these gain-coupled DFB lasers. Gain-switching at 4 GHz with a 100% optical modulation depth and a FWHM pulse width of 23 ps was achieved with these gain-coupled DFB lasers. The peak power was 72 mW and the FWHM bandwidth was 0.14 nm. We also fabricated InGaAs/InGaAsP multiquantum-well DBR lasers by CBE. Taking advantage of uniform thickness growth and proper design of weak and long gratings, a record high SMSR of 58.5 dB was obtained |
BibTeX:
@article{tsang_long-wavelength_1994,
author = {Tsang, W.T. and Wu, M.C. and Chen, Y.K. and Choa, F. -S and Logan, R.A and Chu, S.-N.G. and Sergent, AM. and Magill, P. and Reichmann, K.C. and Burrus, C.A},
title = {Long-wavelength InGaAsP/InP multiquantum well distributed feedback and distributed Bragg reflector lasers grown by chemical beam epitaxy},
journal = {IEEE Journal of Quantum Electronics},
year = {1994},
volume = {30},
number = {6},
pages = {1370--1380},
doi = {10.1109/3.299459}
}
|
| Choa FS, Tsang WT, Logan RA, Gnall RP, Koch TL, Burrus CA, Wu MC, Chen YK and Kapre R (1993), "InGaAs/InGaAsP integrated tunable detector grown by chemical beam epitaxy", Applied Physics Letters., September, 1993. Vol. 63(13), pp. 1836-1838. |
| Abstract: By controlling the thickness of the grating depth with chemical beam epitaxy (CBE) growth time, we report in this letter the design and performance of an integrated tunable detector. A carefully designed tunable active filter, which allows only one below threshold Fabry–Perot mode for operation, is integrated with a waveguide detector. The full tuning range of this kind of tunable device can now be utilized for system applications. |
BibTeX:
@article{choa_ingaas/ingaasp_1993,
author = {Choa, F. S. and Tsang, W. T. and Logan, R. A. and Gnall, R. P. and Koch, T. L. and Burrus, C. A. and Wu, M. C. and Chen, Y. K. and Kapre, R.},
title = {InGaAs/InGaAsP integrated tunable detector grown by chemical beam epitaxy},
journal = {Applied Physics Letters},
year = {1993},
volume = {63},
number = {13},
pages = {1836--1838},
url = {http://scitation.aip.org/content/aip/journal/apl/63/13/10.1063/1.110678},
doi = {10.1063/1.110678}
}
|
| Kapre RM, Tsang WT, Ha NT, Wu MC and Chen YK (1993), "Zinc doping of Ga0.51In0.49P grown on GaAs(100) substrates by chemical beam epitaxy", Applied Physics Letters., May, 1993. Vol. 62(18), pp. 2212-2214. |
| Abstract: We report on the p‐type doping of Ga0.51In0.49P lattice matched to GaAs(100) using gaseous diethylzinc by chemical beam epitaxy. The doping concentration was found to decrease with substrate temperature with an apparent activation energy of 5.3 eV. It was found necessary to keep the substrate temperature below about 500 °C to obtain doping in the 1018/cm3 range. The doping concentration shows a 0.8th power law with increasing dopant flow rate and saturates at approximately 5×1018/cm3. The p‐doped GaInP layers were used as cladding layers for 0.98 μm strained InGaAs/GaAs lasers which show state‐of‐the‐art performance. |
BibTeX:
@article{kapre_zinc_1993,
author = {Kapre, R. M. and Tsang, W. T. and Ha, N. T. and Wu, M. C. and Chen, Y. K.},
title = {Zinc doping of Ga0.51In0.49P grown on GaAs(100) substrates by chemical beam epitaxy},
journal = {Applied Physics Letters},
year = {1993},
volume = {62},
number = {18},
pages = {2212--2214},
url = {http://scitation.aip.org/content/aip/journal/apl/62/18/10.1063/1.109419},
doi = {10.1063/1.109419}
}
|
| Chen Y, Rapre R, Tsang W and Wu M (1992), "InGaP/GaAs/InGaP double heterostructure bipolar transistors with carbon-doped base grown by CBE", Electronics Letters., June, 1992. Vol. 28(13), pp. 1228-1230. |
| Abstract: Carbon-doped InGaP/GaAs/InGaP double heterostructure bipolar transistors with 25 AA setback layer are grown by chemical beam epitaxy. Transistors with nonalloyed base contacts show a very high common emitter current gain of 120 and very low collector saturation voltage of 75 mV at room temperature. |
BibTeX:
@article{chen_ingap/gaas/ingap_1992,
author = {Chen, Y.K. and Rapre, R. and Tsang, W.T. and Wu, M.C.},
title = {InGaP/GaAs/InGaP double heterostructure bipolar transistors with carbon-doped base grown by CBE},
journal = {Electronics Letters},
year = {1992},
volume = {28},
number = {13},
pages = {1228--1230},
doi = {10.1049/el:19920775}
}
|
| Chen YK and Wu MC (1992), "Monolithic colliding-pulse mode-locked quantum-well lasers", IEEE Journal of Quantum Electronics. Vol. 28(10), pp. 2176-2185. |
BibTeX:
@article{chen_monolithic_1992,
author = {Chen, Y. K. and Wu, M. C.},
title = {Monolithic colliding-pulse mode-locked quantum-well lasers},
journal = {IEEE Journal of Quantum Electronics},
year = {1992},
volume = {28},
number = {10},
pages = {2176--2185}
}
|
| Choa F, Tsang W, Logan R, Gnall R, Koren U, Koch T, Burrus C, Wu M, Chen Y, Sciortino P, Sergent A and Corvini P (1992), "Very high sidemode-suppression-ratio distributed-Bragg-reflector lasers grown by chemical beam epitaxy", Electronics Letters., May, 1992. Vol. 28(11), pp. 1001-1002. |
| Abstract: The fabrication and performance of InGaAs/InGaAsP multiquantum well distributed-Bragg-reflector lasers grown by chemical beam epitaxy are reported. Use of a long and weak grating, which was made on a thin and uniformly grown quaternary layer has enabled the grating coupling constant kappa to be well controlled. For most of the lasers the measured linewidths are below 10 MHz. A record high sidemode suppression ratio of 58.5 dB was obtained. |
BibTeX:
@article{choa_very_1992,
author = {Choa, F.S. and Tsang, W.T. and Logan, R.A and Gnall, R.P. and Koren, U. and Koch, T.L. and Burrus, C.A and Wu, M.C. and Chen, Y.K. and Sciortino, P.F. and Sergent, AM. and Corvini, P.J.},
title = {Very high sidemode-suppression-ratio distributed-Bragg-reflector lasers grown by chemical beam epitaxy},
journal = {Electronics Letters},
year = {1992},
volume = {28},
number = {11},
pages = {1001--1002},
doi = {10.1049/el:19920636}
}
|
| Hobson WS, Chen YK and Wu MC (1992), "InGaAs/AlGaAs ridge waveguide lasers utilizing an InGaP etch-stop layer", Semiconductor Science and Technology., November, 1992. Vol. 7(11), pp. 1425. |
| Abstract: An InGaP etch-stop layer was used to control the mesa height in a ridge waveguide InGaAs/AlGaAs strained multiple quantum well laser grown by organometallic vapour phase epitaxy. These 950 nm lasers exhibited internal quantum efficiencies of eta i=0.99 and very low internal losses of alpha i=2.6 cm-1. For a cavity length of 500 mu m, a threshold current of 12 mA was obtained. The high performance of these lasers and the improved uniformity of their characteristics demonstrate the utility of InGaP etch-stop layers in improving process yield without detrimental effects. |
BibTeX:
@article{hobson_ingaas/algaas_1992,
author = {Hobson, W. S. and Chen, Y. K. and Wu, M. C.},
title = {InGaAs/AlGaAs ridge waveguide lasers utilizing an InGaP etch-stop layer},
journal = {Semiconductor Science and Technology},
year = {1992},
volume = {7},
number = {11},
pages = {1425},
url = {http://iopscience.iop.org/0268-1242/7/11/024},
doi = {10.1088/0268-1242/7/11/024}
}
|
| Hobson WS, Wu MC, Chen YK, Chin MA, Geva M and Jones KS (1992), "Periodic index separate confinement heterostructure InGaAs/AlGaAs multiple quantum well laser grown by organometallic vapor phase epitaxy", Applied Physics Letters., February, 1992. Vol. 60(5), pp. 598-600. |
| Abstract: Organometallic vapor phase epitaxy was used to grow a novel periodic index separate confinement heterostructure (PINSCH) InGaAs/AlGaAs multiple quantum well(MQW) laser. Secondary ion mass spectrometry and transmission electron microscopy were used to characterize the structure. The performance of the PINSCH laser was compared with that of a graded index separate confinement heterostructure (GRINSCH) MQW laser grown under similar conditions. The PINSCH laser uses cladding layers comprised of periodic semiconductor multilayers (Al0.4Ga0.6As/GaAs) which provide both optical and electrical confinement. Since the optical field decays over several multilayers, and therefore is far less tightly confined than in the GRINSCH structure, a significant reduction of the transverse far‐field angle occurs. Comparing the performance of 5×750 μm self‐aligned ridge waveguide InGaAs/AlGaAs lasers emitting at 980 nm, the PINSCH structure exhibits a transverse far‐field angle of 23° compared to 46° for the GRINSCH. This is obtained at the expense of a modest increase in threshold current (19 mA vs 10 mA). |
BibTeX:
@article{hobson_periodic_1992,
author = {Hobson, W. S. and Wu, M. C. and Chen, Y. K. and Chin, M. A. and Geva, M. and Jones, K. S.},
title = {Periodic index separate confinement heterostructure InGaAs/AlGaAs multiple quantum well laser grown by organometallic vapor phase epitaxy},
journal = {Applied Physics Letters},
year = {1992},
volume = {60},
number = {5},
pages = {598--600},
url = {http://scitation.aip.org/content/aip/journal/apl/60/5/10.1063/1.106565},
doi = {10.1063/1.106565}
}
|
| Hong M, Wu MC, Chen YK, Mannaerts JP and Chin MA (1992), "MBE growth and characteristics of periodic index separate confinement heterostructure InGaAs quantum-well lasers", Journal of electronic materials. Vol. 21(2), pp. 181–185. |
BibTeX:
@article{hong_mbe_1992,
author = {Hong, M. and Wu, M. C. and Chen, Y. K. and Mannaerts, J. P. and Chin, M. A.},
title = {MBE growth and characteristics of periodic index separate confinement heterostructure InGaAs quantum-well lasers},
journal = {Journal of electronic materials},
year = {1992},
volume = {21},
number = {2},
pages = {181–185},
url = {http://link.springer.com/article/10.1007/BF02655834}
}
|
| Hong M, Chen YK, Wu MC, Vandenberg JM, Chu SNG, Mannaerts JP and Chin MA (1992), "Periodic index separate confinement heterostructure InGaAs/AlGaAs quantum well lasers grown by temperature modulation molecular beam epitaxy", Applied Physics Letters., July, 1992. Vol. 61(1), pp. 43-45. |
| Abstract: Solid‐sourcemolecular beam epitaxy with substrate temperature modulation has produced periodic index separate confinement heterostructure InGaAs/AlGaAs quantum well lasers with greatly improved performance. These lasers in a broad area geometry are under room‐temperature continuous wave operation and have low threshold current density of 300 A/cm2, high internal quantum efficiency of 91 low internal waveguide loss of 2.2 cm−1, a reduced transverse beam divergence of 30°, and a high characteristic temperature of 187 K. |
BibTeX:
@article{hong_periodic_1992,
author = {Hong, M. and Chen, Y. K. and Wu, M. C. and Vandenberg, J. M. and Chu, S. N. G. and Mannaerts, J. P. and Chin, M. A.},
title = {Periodic index separate confinement heterostructure InGaAs/AlGaAs quantum well lasers grown by temperature modulation molecular beam epitaxy},
journal = {Applied Physics Letters},
year = {1992},
volume = {61},
number = {1},
pages = {43--45},
url = {http://scitation.aip.org/content/aip/journal/apl/61/1/10.1063/1.107662},
doi = {10.1063/1.107662}
}
|
| Hong M, Wu MC, Chen YK, Mannaerts JP and Chin MA (1992), "Temperature modulation molecular‐beam epitaxy and its application to the growth of periodic index separate confinement heterostructure InGaAs quantum‐well lasers", Journal of Vacuum Science & Technology B., March, 1992. Vol. 10(2), pp. 989-991. |
| Abstract: Solid‐source molecular‐beam epitaxy has been employed to grow periodic index separate confinement heterostructure InGaAs quantum‐well lasers emitting at 980 nm. The 5 μm×750 μm device fabricated using a self‐aligned process has far‐field angles of 10° by 20°, a threshold current of 45 mA, an external differential quantum efficiency of 1.15 mW/mA (90, and an output power of 620 mW, all measured at room temperature under cw operation. A record high fiber coupling efficiency of 51% has been achieved. |
BibTeX:
@article{hong_temperature_1992,
author = {Hong, M. and Wu, M. C. and Chen, Y. K. and Mannaerts, J. P. and Chin, M. A.},
title = {Temperature modulation molecular‐beam epitaxy and its application to the growth of periodic index separate confinement heterostructure InGaAs quantum‐well lasers},
journal = {Journal of Vacuum Science & Technology B},
year = {1992},
volume = {10},
number = {2},
pages = {989--991},
url = {http://scitation.aip.org/content/avs/journal/jvstb/10/2/10.1116/1.586109},
doi = {10.1116/1.586109}
}
|
| Kapre RM, Tsang WT, Chen YK, Wu MC, Chin MA and Choa FS (1992), "Chemical beam epitaxy of GaInP on GaAs(100) substrates and its application to 0.98 μm lasers", Journal of Crystal Growth., November, 1992. Vol. 124(1–4), pp. 176-180. |
| Abstract: We present results on the growth, doping, and application to lasers of GaInP on GaAs(100) substrates using chemical beam epitaxy (CBE). The growth studies were performed in the substrate temperature range of 490–555°C. We were able to obtain lattice-matching with good surface morphology over the entire substrate range investigated. For a fixed triethylgallium (TEGa) flow, a sharp increase in the trimethylindium (TMIn) flow required to obtain lattice-matching for Tsub above 520°C is observed. This can be attributed to an increase in GaP growth rate and a decrease in InP growth rate due to desorption of TMIn species. The p-type and n-type doping of Ga0.51In0.49P was investigated using diethylzinc (DEZn) and hydrogen sulfide (H2S), respectively. It was found that low substrate temperature (≲ 510°C) was necessary to obtain high p-type doping. Separate confinement heterostructure (SCH) lasers with strained In0.2Ga0.8As/GaAs multiple-quantum-well (MQW) active layers and Ga0.51In0.49P cladding layers for operation at 0.98 μm were grown. Broad-area lasers show extremely low threshold current densities, Jth, of 70 A/cm2. Ridge waveguide lasers with 4 μm stripe width have a threshold of 7.8 mA and gave linear CW output powers upto 100 mW. High external quantum efficiency of 0.9 mW/mA and a very low internal waveguide loss of 2.5 cm-1 were obtained from these lasers. |
BibTeX:
@article{kapre_chemical_1992,
author = {Kapre, R. M. and Tsang, W. T. and Chen, Y. K. and Wu, M. C. and Chin, M. A. and Choa, F. S.},
title = {Chemical beam epitaxy of GaInP on GaAs(100) substrates and its application to 0.98 μm lasers},
journal = {Journal of Crystal Growth},
year = {1992},
volume = {124},
number = {1–4},
pages = {176--180},
url = {http://www.sciencedirect.com/science/article/pii/002202489290456S},
doi = {10.1016/0022-0248(92)90456-S}
}
|
| Tsang WT, Choa FS, Wu MC, Chen YK, Logan RA, Chu SNG, Sergent AM, Magill P, Reichmann KC and Burrus CA (1992), "Long wavelength InGaAsP/InP distributed feedback lasers grown by chemical beam epitaxy", Journal of Crystal Growth., November, 1992. Vol. 124(1–4), pp. 716-722. |
| Abstract: We have demonstrated successful operation of long wavelength InGaAsP low threshold-current gain-coupled DFB lasers. This is accomplished by using a InGaAsP quarternary grating or quantum well grating that absorbs the DFB emission. The use of a quantum well grating, in particular, greatly facilitates the reproducible regrowth (defect-free) over grating and the control of the coupling coefficient. CW threshold currents were in the range of 10–15 mA for 250 μm and 13–18 mA for 250 and 500 μm cavities, respectively. Slope efficiencies were high, ∼0.4 mW/mA (both facets). SMSR was as high as 52 kB and remained in the same DFB mode with SMSR staying ∼50 dB throughout the entire current range. Linewidth x power products of 1.9-4.0 were measured with minimum linewidths of 1.8-2.2 MHz. No detectable chirp was measured under 2.5 Gb/s modulation. Unlike index-coupled DFB lasers in which mode partition events decrease slowly even when biased above threshold, these lasers have mode partition events shut off sharply as bias approaches threshold (≿0.95 Ith). A very small dispersion penalty of 1.0 dB was measured at 10-11 BER in transmission experiments using these lasers as sources at 1.7 Gb/s over an amplified fiber system of 239 km. No self-pulsation was observed in these gain-coupled DFB lasers. |
BibTeX:
@article{tsang_long_1992,
author = {Tsang, W. T. and Choa, F. S. and Wu, M. C. and Chen, Y. K. and Logan, R. A. and Chu, S. N. G. and Sergent, A. M. and Magill, P. and Reichmann, K. C. and Burrus, C. A.},
title = {Long wavelength InGaAsP/InP distributed feedback lasers grown by chemical beam epitaxy},
journal = {Journal of Crystal Growth},
year = {1992},
volume = {124},
number = {1–4},
pages = {716--722},
url = {http://www.sciencedirect.com/science/article/pii/002202489290541P},
doi = {10.1016/0022-0248(92)90541-P}
}
|
| Tsang W, Choa FS, Wu M, Chen Y-K, Logan R, Sergent A and Burrus C (1992), "Long-wavelength InGaAsP/InP distributed feedback lasers incorporating gain-coupled mechanism", IEEE Photonics Technology Letters., March, 1992. Vol. 4(3), pp. 212-215. |
| Abstract: Successful operation of long-wavelength InGaAsP low-threshold-current gain-coupled DFB lasers was demonstrated by using an InGaAsP quaternary grating that absorbs the DFB (distributed feedback) emission. The amount of gain (loss)-coupling is controlled by the composition (bandgap) and thickness of the grating quaternary and the InP-spacer layer between the grating and the active layer. With optimally designed lasers, CW (continuous-wave) threshold currents were 10-15 mA (250- mu m cavity, as-cleaved), slope efficiency was approximately 0.4 mW/mA (both facets) and SMSR (side-mode suppression ratio) was as high as 52 dB. The laser operated in the same DFB mode with SMSR staying approximately 50 dB throughout the entire current range. At 100 degrees C, the CW threshold current stayed low, approximately 50 mA, and SMSR was approximately 40 dB. Results also indicate that the presence of gain-coupling removes the degeneracy in lasing wavelength.textlesstextgreater |
BibTeX:
@article{tsang_long-wavelength_1992,
author = {Tsang, W.T. and Choa, F. -S and Wu, M.C. and Chen, Y.-K. and Logan, R.A and Sergent, AM. and Burrus, C.A},
title = {Long-wavelength InGaAsP/InP distributed feedback lasers incorporating gain-coupled mechanism},
journal = {IEEE Photonics Technology Letters},
year = {1992},
volume = {4},
number = {3},
pages = {212--215},
doi = {10.1109/68.122369}
}
|
| Tsang WT, Kapre R, Wu MC and Chen YK (1992), "Low‐threshold InGaAs strained‐layer quantum well lasers (λ=0.98 μm) with GaInP cladding layers prepared by chemical beam epitaxy", Applied Physics Letters., August, 1992. Vol. 61(7), pp. 755-757. |
| Abstract: We report on the InGaAs/GaAs/GaInP strained‐layer quantum well(QW) lasers grown by chemical beam epitaxy (CBE). The single QW broad‐area layers have a very low threshold current density of 70 A/cm2, which is among the lowest value reported for InGaAs/GaAs/GaInP lasers. Ridge‐waveguide lasers emitting at 0.98 μm have a continuous wave (cw) threshold of 7.8 mA for a 500‐μm‐long cavity and a differential quantum efficiency as high as 0.9 mW/mA. Internal quantum efficiency of 0.95 and internal waveguide losses of 2.5 cm−1 were obtained. Linear cw output power of 100 mW was obtained. These results demonstrate that CBE is capable of growing 0.98 μm InGaAs strained‐layer QW lasers having performance similar to the best prepared by other epitaxialgrowth techniques. |
BibTeX:
@article{tsang_lowthreshold_1992,
author = {Tsang, W. T. and Kapre, R. and Wu, M. C. and Chen, Y. K.},
title = {Low‐threshold InGaAs strained‐layer quantum well lasers (λ=0.98 μm) with GaInP cladding layers prepared by chemical beam epitaxy},
journal = {Applied Physics Letters},
year = {1992},
volume = {61},
number = {7},
pages = {755--757},
url = {http://scitation.aip.org/content/aip/journal/apl/61/7/10.1063/1.107788},
doi = {10.1063/1.107788}
}
|
| Tsang WT, Choa FS, Wu MC, Chen YK, Logan RA, Chu SNG, Sergent AM and Burrus CA (1992), "Semiconductor distributed feedback lasers with quantum well or superlattice gratings for index or gain‐coupled optical feedback", Applied Physics Letters., May, 1992. Vol. 60(21), pp. 2580-2582. |
| Abstract: We introduce a semiconductor distributed feedback (DFB) in which the grating is fabricated out of quantum well(QW) or superlatticemultilayers. This approach provides a very simple and effective scheme for achieving gain (loss)‐coupled DFB lasers. The present idea was successfully demonstrated with a 1.55‐μm wavelength 6‐QW In0.6Ga0.4As (5 nm)/InGaAsP (band‐gap wavelength=1.25 μm, 18.6 nm) separate confinement heterostructure DFB laser utilizing only a 2‐QW In0.62Ga0.38As (4 nm)/InP (9.3 nm) as the grating. |
BibTeX:
@article{tsang_semiconductor_1992,
author = {Tsang, W. T. and Choa, F. S. and Wu, M. C. and Chen, Y. K. and Logan, R. A. and Chu, S. N. G. and Sergent, A. M. and Burrus, C. A.},
title = {Semiconductor distributed feedback lasers with quantum well or superlattice gratings for index or gain‐coupled optical feedback},
journal = {Applied Physics Letters},
year = {1992},
volume = {60},
number = {21},
pages = {2580--2582},
url = {http://scitation.aip.org/content/aip/journal/apl/60/21/10.1063/1.106915},
doi = {10.1063/1.106915}
}
|
| Wu M, Chen Y-K, Kuo J, Chin MA and Sergent A (1992), "High temperature, high power InGaAs/GaAs quantum-well lasers with lattice-matched InGaP cladding layers", IEEE Photonics Technology Letters., July, 1992. Vol. 4(7), pp. 676-679. |
| Abstract: The authors report the high-temperature and high-power operation of strained-layer InGaAs/GaAs quantum well lasers with lattice-matched InGaP cladding layers grown by gas-source molecular beam epitaxy. Self-aligned ridge waveguide lasers of 3- mu m width were fabricated. These lasers have low threshold currents (7 mA for 250- mu m-long cavity and 12 mA for 500- mu m-long cavity), high external quantum efficiencies (0.9 mW/mA), and high peak powers (160 mW for 3- mu m-wide lasers and 285 mW for 5- mu m-wide laser) at room temperature under continuous wave (CW) conditions. The CW operating temperature of 185 degrees C is the highest ever reported for InGaAs/GaAs/InGaP quantum well lasers, and is comparable to the best result (200 degrees C) reported for InGaAs/GaAs/AlGaAs lasers.textlesstextgreater |
BibTeX:
@article{wu_high_1992,
author = {Wu, M.C. and Chen, Y.-K. and Kuo, J.M. and Chin, M. A and Sergent, AM.},
title = {High temperature, high power InGaAs/GaAs quantum-well lasers with lattice-matched InGaP cladding layers},
journal = {IEEE Photonics Technology Letters},
year = {1992},
volume = {4},
number = {7},
pages = {676--679},
doi = {10.1109/68.145235}
}
|
| Chen Y-K, Wu M, Hobson W, Pearton S, Sergent A and Chin MA (1991), "High-power 980-nm AlGaAs/InGaAs strained quantum-well laser grown by OMVPE", IEEE Photonics Technology Letters., May, 1991. Vol. 3(5), pp. 406-408. |
| Abstract: High-power lattice-strained AlGaAs/InGaAs graded index separate-confinement heterostructure (GRINSCH) quantum-well lasers emitting at a 980-nm wavelength have been grown by organometallic vapor phase epitaxy (OMVPE) and fabricated with a self-aligned ridge-waveguide structure. Using a 3- mu m-wide and 750- mu m-long AR-HR coated laser, 30 mV of optical power was coupled into optical fibers with 28.6% efficiency. A dominating single-lobe far-field radiation pattern was obtained from a wedge-shaped ridge-waveguide laser for output power as high as 240 mW with a maximum output power of 310 mW.textlesstextgreater |
BibTeX:
@article{chen_high-power_1991,
author = {Chen, Y.-K. and Wu, M.C. and Hobson, W.S. and Pearton, S.J. and Sergent, AM. and Chin, M. A},
title = {High-power 980-nm AlGaAs/InGaAs strained quantum-well laser grown by OMVPE},
journal = {IEEE Photonics Technology Letters},
year = {1991},
volume = {3},
number = {5},
pages = {406--408},
doi = {10.1109/68.93860}
}
|
| Chen YK, Wu MC, Hobson WS, Chin MA, Choquette KD, Freund RS and Sergent AM (1991), "High‐temperature operation of periodic index separate confinement heterostructure quantum well laser", Applied Physics Letters., November, 1991. Vol. 59(22), pp. 2784-2786. |
| Abstract: High‐temperature operation of the InGaAs/GaAs/AlGaAs quantum well lasers with an expanded vertical optical mode is demonstrated for the first time using a periodic index separate confinement heterostructure (PINSCH) laser. Continuous wave (cw) operation up to 145 °C is achieved with a coated 3 μm×508 μm PINSCH laser. The measured characteristic temperature (170 K) and external differential quantum efficiency (0.75 mW/mA) are comparable to those obtained in a graded index separate confinement heterostructure laser fabricated at the same time. These results illustrate the excellent capability of the PINSCH laser to compress the transverse beam divergence without sacrificing the electrical carrier confinement. |
BibTeX:
@article{chen_hightemperature_1991,
author = {Chen, Y. K. and Wu, M. C. and Hobson, W. S. and Chin, M. A. and Choquette, K. D. and Freund, R. S. and Sergent, A. M.},
title = {High‐temperature operation of periodic index separate confinement heterostructure quantum well laser},
journal = {Applied Physics Letters},
year = {1991},
volume = {59},
number = {22},
pages = {2784--2786},
url = {http://scitation.aip.org/content/aip/journal/apl/59/22/10.1063/1.105859},
doi = {10.1063/1.105859}
}
|
| Chen Y-K, Wu M, Tanbun-Ek T, Logan R and Chin MA (1991), "Multicolor single-wavelength sources generated by a monolithic colliding pulse mode-locked quantum well laser", IEEE Photonics Technology Letters., November, 1991. Vol. 3(11), pp. 971-973. |
| Abstract: The authors report on the separation of single longitudinal modes from the mode-locked program spectrum of a 300-GHz monolithic colliding pulse mode-locked (CPM) semiconductor quantum-well laser. Experimentally, the selected longitudinal mode shows a 10-dB reduction of low-frequency relative intensity noise compared to that of the selected mode from the same laser in continuous-wave (CW) lasing conditions. The strong phase coherence among the passively mode-locked longitudinal modes reduces the partition noise of the unlocked CW laser.textlesstextgreater |
BibTeX:
@article{chen_multicolor_1991,
author = {Chen, Y.-K. and Wu, M.C. and Tanbun-Ek, T. and Logan, R.A and Chin, M. A},
title = {Multicolor single-wavelength sources generated by a monolithic colliding pulse mode-locked quantum well laser},
journal = {IEEE Photonics Technology Letters},
year = {1991},
volume = {3},
number = {11},
pages = {971--973},
doi = {10.1109/68.97830}
}
|
| Chen YK, Wu MC, Kuo JM, Chin MA and Sergent AM (1991), "Self‐aligned InGaAs/GaAs/InGaP quantum well lasers prepared by gas‐source molecular beam epitaxy with two growth steps", Applied Physics Letters., December, 1991. Vol. 59(23), pp. 2929-2931. |
| Abstract: Index‐guided self‐aligned InGaAs/GaAs/InGaP quantum well lasers are fabricated by gas‐source molecular beam epitaxy in two growth sequences on a GaAs substrate for the first time. The use of aluminum‐free InGaP as cladding layers permits regrowth steps without the problem with the oxidation of aluminum alloys. A patterned n‐InGaP current confinement layer is used to provide index guiding as well as current blocking. Preliminary results from coated 2.5‐μm‐wide and 508‐μm‐long devices show a room temperature continuous wave lasing threshold current of 12 mA with an external differential quantum efficiency of 0.68 mW/mA and a characteristic temperature of 130 K from 30 to 75 °C. |
BibTeX:
@article{chen_selfaligned_1991,
author = {Chen, Y. K. and Wu, M. C. and Kuo, J. M. and Chin, M. A. and Sergent, A. M.},
title = {Self‐aligned InGaAs/GaAs/InGaP quantum well lasers prepared by gas‐source molecular beam epitaxy with two growth steps},
journal = {Applied Physics Letters},
year = {1991},
volume = {59},
number = {23},
pages = {2929--2931},
url = {http://scitation.aip.org/content/aip/journal/apl/59/23/10.1063/1.105854},
doi = {10.1063/1.105854}
}
|
| Chen YK, Wu MC, Tanbun‐Ek T, Logan RA and Chin MA (1991), "Subpicosecond monolithic colliding‐pulse mode‐locked multiple quantum well lasers", Applied Physics Letters., March, 1991. Vol. 58(12), pp. 1253-1255. |
| Abstract: Ultrafast subpicosecond optical pulse generation is achieved by passive colliding‐pulse mode locking of monolithic multiple quantum wellInGaAsPsemiconductor lasers. Transform‐limited optical pulses with durations of 1.1, 0.83, 1.0, and 0.64 ps are achieved at repetition rates of 40, 80, 160, and 350 GHz, respectively, without using any external ac sources. |
BibTeX:
@article{chen_subpicosecond_1991,
author = {Chen, Y. K. and Wu, M. C. and Tanbun‐Ek, T. and Logan, R. A. and Chin, M. A.},
title = {Subpicosecond monolithic colliding‐pulse mode‐locked multiple quantum well lasers},
journal = {Applied Physics Letters},
year = {1991},
volume = {58},
number = {12},
pages = {1253--1255},
url = {http://scitation.aip.org/content/aip/journal/apl/58/12/10.1063/1.104327},
doi = {10.1063/1.104327}
}
|
| Kuo JM, Chen YK, Wu MC and Chin MA (1991), "InGaAs/GaAs/InGaP multiple‐quantum‐well lasers prepared by gas‐source molecular beam epitaxy", Applied Physics Letters., November, 1991. Vol. 59(22), pp. 2781-2783. |
| Abstract: We report on the first room‐temperature operation of aluminum‐free In0.2Ga0.8As/GaAs/ In0.49Ga0.51P multiple‐quantum‐well lasers grown by gas‐source molecular beam epitaxy. These lasers have low threshold current densityJ th of 177 A/cm2, high internal quantum efficiency of 91 and low internal waveguide loss of 9.1 cm−1. The characteristic temperature T 0 is 150 K, which is the highest value ever reported. These results demonstrate that gas‐source molecular beam epitaxy is suitable for growing high‐quality In0.2Ga0.8As/GaAs/In0.49Ga0.51P lasers. |
BibTeX:
@article{kuo_ingaas/gaas/ingap_1991,
author = {Kuo, J. M. and Chen, Y. K. and Wu, M. C. and Chin, M. A.},
title = {InGaAs/GaAs/InGaP multiple‐quantum‐well lasers prepared by gas‐source molecular beam epitaxy},
journal = {Applied Physics Letters},
year = {1991},
volume = {59},
number = {22},
pages = {2781--2783},
url = {http://scitation.aip.org/content/aip/journal/apl/59/22/10.1063/1.105858},
doi = {10.1063/1.105858}
}
|
| Tanbun-Ek T, Logan RA, Temkin H, Olsson NA, Wu MC, Sergent AM and Wecht KW (1991), "Reproducible growth of narrow linewidth multiple quantum well graded index separate confinement distributed feedback (MQW-GRIN-SCH-DFB) lasers by MOVPE", Journal of Crystal Growth., January, 1991. Vol. 107(1–4), pp. 751-756. |
| Abstract: We describe reproducible growth of multiple quantum well graded index separate confinement distributed feedback (MQW- GRIN-SCH-DFB) lasers by atmospheric pressure metalorganic vapor phase epitaxy (MOVPE). Epitaxial layers were grown directly on a first order grating prepared on a (100) n-InP substrate. The gratings were preserved by introducing a suitable mixture of AsH3 and PH3 into the reactor. The quality of epitaxial layers grown on preserved gratings was found to improve by deposition of a very thin quaternary layer (7 nm thick) at low temperature (500°C), before the growth of the waveguide and subsequent graded index layers at the normal growth temperature (625°C). With the cavity length varied from 0.5 to 2 mm, the corresponding threshold currents were 22 and 100 mA, respectively. A remarkable improvement in both laser linewidth and output power was observed with devices as long as 2–3 mm. With 2 mm long device we observed linewidth as narrow as 600 kHz at a power output of 35 mW. |
BibTeX:
@article{tanbun-ek_reproducible_1991,
author = {Tanbun-Ek, T. and Logan, R. A. and Temkin, H. and Olsson, N. A. and Wu, M. C. and Sergent, A. M. and Wecht, K. W.},
title = {Reproducible growth of narrow linewidth multiple quantum well graded index separate confinement distributed feedback (MQW-GRIN-SCH-DFB) lasers by MOVPE},
journal = {Journal of Crystal Growth},
year = {1991},
volume = {107},
number = {1–4},
pages = {751--756},
url = {http://www.sciencedirect.com/science/article/pii/002202489190552G},
doi = {10.1016/0022-0248(91)90552-G}
}
|
| Tsang WT, Choa FS, Logan RA, Tanbun‐Ek T, Wu MC, Chen YK, Sergent AM and Wecht KW (1991), "1.3 μm InGaAsP/InP multiquantum well buried heterostructure lasers grown by chemical‐beam epitaxy", Applied Physics Letters., December, 1991. Vol. 59(24), pp. 3084-3086. |
| Abstract: High performance InGaAsP/InP multiquantum well (MQW) buried heterostructure lasers emitting around 1.3 μm were prepared for the first time by chemical‐beam epitaxy. At 20 °C, continuous‐wave (cw) threshold currents were 5–8 mA and quantum efficiencies were 0.35–0.45 mW/mA for 250 μm long lasers having one facet ∼85% reflective coated. At 80 °C, the cw threshold currents remained low, 23 mA, quantum efficiency stayed high, 0.22 mW/mA, and output power of ∼10 mW was achieved. cw power output as high as 125 mW was achieved with 750 μm long lasers having AR–HR (∼585 coatings. Lasers with bulk active were also studied for comparison. Though they also have excellent device performance, in general, they are somewhat inferior to MQW lasers. |
BibTeX:
@article{tsang_1.3_1991,
author = {Tsang, W. T. and Choa, F. S. and Logan, R. A. and Tanbun‐Ek, T. and Wu, M. C. and Chen, Y. K. and Sergent, A. M. and Wecht, K. W.},
title = {1.3 μm InGaAsP/InP multiquantum well buried heterostructure lasers grown by chemical‐beam epitaxy},
journal = {Applied Physics Letters},
year = {1991},
volume = {59},
number = {24},
pages = {3084--3086},
url = {http://scitation.aip.org/content/aip/journal/apl/59/24/10.1063/1.105796},
doi = {10.1063/1.105796}
}
|
| Tsang WT, Choa FS, Wu MC, Chen YK, Logan RA, Tanbun‐Ek T, Chu SNG, Tai K, Sergent AM and Wecht KW (1991), "1.5 μm wavelength InGaAs/InGaAsP distributed feedback multi‐quantum‐well lasers grown by chemical beam epitaxy", Applied Physics Letters., November, 1991. Vol. 59(19), pp. 2375-2377. |
| Abstract: We demonstrated the first successful growth of 1.5 μm strained‐layer InGaAs/InGaAsP multi‐quantum‐well (MQW) distributed feedback (DFB) lasers by chemical beam epitaxy (CBE). In these DFB wafers, a quaternary grating is placed at the bottom of the MQW stack with an InP spacer layer. Studies by transmission electron microscopy show that defect‐free InP regrowth was achieved with no mass transport needed over the grating corrugations before regrowth. With CBE regrowth the shapes of the gratings were well preserved. The InP overlayer also very effectively smoothed out the quaternary surface corrugations resulting in very flat MQW structures. Buried‐heterostructure 6‐QW DFB lasers (250 μm long and as‐cleaved) operated at 1.55 μm with cw threshold currents 10–15 mA and slope efficiencies up to 0.35 mW/mA (both facets). Side‐mode suppression ratios (SMSR) as high as 49 dB was obtained. The laser operated in the same DFB mode with SMSR staying above 40 dB from threshold and throughout the entire current range even at high temperatures (70 °C checked). |
BibTeX:
@article{tsang_1.5_1991,
author = {Tsang, W. T. and Choa, F. S. and Wu, M. C. and Chen, Y. K. and Logan, R. A. and Tanbun‐Ek, T. and Chu, S. N. G. and Tai, K. and Sergent, A. M. and Wecht, K. W.},
title = {1.5 μm wavelength InGaAs/InGaAsP distributed feedback multi‐quantum‐well lasers grown by chemical beam epitaxy},
journal = {Applied Physics Letters},
year = {1991},
volume = {59},
number = {19},
pages = {2375--2377},
url = {http://scitation.aip.org/content/aip/journal/apl/59/19/10.1063/1.106020},
doi = {10.1063/1.106020}
}
|
| Tsang W, Yang L, Wu M and Chen Y (1991), "Selective area epitaxy and growth over patterned substrates by chemical beam epitaxy", Electronics Letters., January, 1991. Vol. 27(1), pp. 3-5. |
| Abstract: Selective area epitaxy and growth over patterned substrate using chemical beam epitaxy (CBE) were investigated. Truly selective area epitaxy with no deposition over the SiO2 masks has been routinely obtained with excellent epilayer morphology. Uniform coverage was obtained for regrowth over etched mesas to form buried heterostructures. For growth over etch channels, very unique growth characteristics were obtained. Buried crescent stripes similar to those formed by liquid-phase epitaxy inside channels were also obtained by CBE. These growth characteristics demonstrated the unique of CBE for diode laser fabrication. |
BibTeX:
@article{tsang_selective_1991,
author = {Tsang, W.T. and Yang, L. and Wu, M.C. and Chen, Y.K.},
title = {Selective area epitaxy and growth over patterned substrates by chemical beam epitaxy},
journal = {Electronics Letters},
year = {1991},
volume = {27},
number = {1},
pages = {3--5},
doi = {10.1049/el:19910003}
}
|
| Tsang WT, Choa FS, Wu MC, Chen YK, Sergent AM and Jr PFS (1991), "Very low threshold single quantum well graded‐index separate confinement heterostructure InGaAs/InGaAsP lasers grown by chemical beam epitaxy", Applied Physics Letters., June, 1991. Vol. 58(23), pp. 2610-2612. |
| Abstract: We have succeeded in preparing 1.5 μm wavelength strained‐layer graded‐index separate confinement heterostructure (GRINSCH) InGaAs/InGaAsP single quantum well(SQW) injection lasers by chemical beam epitaxy (CBE). These lasers have extremely low threshold current densityJ th of 170 A/cm2, internal quantum efficiency of 83 and internal waveguide loss of 3.8 cm−1. To the best of our knowledge, these results represent the best values obtained thus far from long‐wavelength InGaAs/InGaAsP quantum well injection lasers grown by any techniques. However, despite the recent rapid reduction in J th, the threshold‐temperature dependence remains poor (T 0=45 K) even in these very low J th GRINSCH SQW lasers. |
BibTeX:
@article{tsang_very_1991,
author = {Tsang, W. T. and Choa, F. S. and Wu, M. C. and Chen, Y. K. and Sergent, A. M. and Jr, P. F. Sciortino},
title = {Very low threshold single quantum well graded‐index separate confinement heterostructure InGaAs/InGaAsP lasers grown by chemical beam epitaxy},
journal = {Applied Physics Letters},
year = {1991},
volume = {58},
number = {23},
pages = {2610--2612},
url = {http://scitation.aip.org/content/aip/journal/apl/58/23/10.1063/1.104838},
doi = {10.1063/1.104838}
}
|
| Wu MC, Chen YK, Hong M, Mannaerts JP, Chin MA and Sergent AM (1991), "A periodic index separate confinement heterostructure quantum well laser", Applied Physics Letters., August, 1991. Vol. 59(9), pp. 1046-1048. |
| Abstract: A novel edge‐emitting periodic index separate confinement heterostructure (PINSCH) semiconductorquantum well laser is proposed and demonstrated for the first time. Periodic semiconductormultilayers are used as optical confinement layers to simultaneously reduce the transverse beam divergence and increase the maximum output power. Self‐aligned ridge‐waveguide InGaAs/GaAs/AlGaAs PINSCH quantum well lasers emitting at 980 nm are fabricated. The 5×750 μm device has far‐field angles of 10° by 20°, a threshold current of 45 mA, an external differential quantum efficiency of 1.15 mW/mA (90, and an output power exceeding 620 mW, all measured at room temperature under CW operation. A record high fiber coupling efficiency of 51% has been achieved with a lensed fiber of 5 μm core diameter. |
BibTeX:
@article{wu_periodic_1991,
author = {Wu, M. C. and Chen, Y. K. and Hong, M. and Mannaerts, J. P. and Chin, M. A. and Sergent, A. M.},
title = {A periodic index separate confinement heterostructure quantum well laser},
journal = {Applied Physics Letters},
year = {1991},
volume = {59},
number = {9},
pages = {1046--1048},
url = {http://scitation.aip.org/content/aip/journal/apl/59/9/10.1063/1.106340},
doi = {10.1063/1.106340}
}
|
| Wu M, Chen Y-K, Tanbun-Ek T, Logan R and Chin MA (1991), "Tunable monolithic colliding pulse mode-locked quantum-well lasers", IEEE Photonics Technology Letters., October, 1991. Vol. 3(10), pp. 874-876. |
| Abstract: The tunabilities of both the wavelength and the pulse-width of monolithic mode-locked semiconductor lasers are demonstrated. Pulses shorter than 1.6 ps, tunable over 8.8 mu m, have been generated by a temperature-tuned monolithic colliding pulse mode-locked (CPM) quantum-well laser. For a fixed wavelength, the pulse-width is independently controlled from 1.2 ps to longer than 3 ps by external bandpass filters. Near transform-limited time-bandwidth products of 0.34 were maintained throughout the tuning processes.textlesstextgreater |
BibTeX:
@article{wu_tunable_1991,
author = {Wu, M.C. and Chen, Y.-K. and Tanbun-Ek, T. and Logan, R.A and Chin, M. A},
title = {Tunable monolithic colliding pulse mode-locked quantum-well lasers},
journal = {IEEE Photonics Technology Letters},
year = {1991},
volume = {3},
number = {10},
pages = {874--876},
doi = {10.1109/68.93246}
}
|
| Yang L, Wu M, Chen Y-K, Tsang W, Chu S-N and Sergent A (1991), "A new InGaAs/InGaAsP delta -strained multiple-quantum-well laser grown by chemical-beam epitaxy", IEEE Photonics Technology Letters., May, 1991. Vol. 3(5), pp. 430-432. |
| Abstract: The authors propose and demonstrate a delta -strained multiple-quantum-well laser in which the quantum well is composed of a thin strained layer ( approximately AA In/sub x/Ga/sub 1-x/As) sandwiched by lattice-matched (In/sub 0.53/Ga/sub 0.47/As) layers. A threshold current density of 510 A/cm/sup 2 /was obtained from broad-area lasers with four delta -strained quantum wells and a cavity length of 3 mm, with an emission wavelength near 1.55 mu m. The use of a delta -strained quantum well provides an additional degree of freedom in optimizing the amount of strain and thickness of the active layer in improving the device performance.textlesstextgreater |
BibTeX:
@article{yang_new_1991,
author = {Yang, L. and Wu, M.C. and Chen, Y.-K. and Tsang, W.T. and Chu, S.-N.G. and Sergent, AM.},
title = {A new InGaAs/InGaAsP delta -strained multiple-quantum-well laser grown by chemical-beam epitaxy},
journal = {IEEE Photonics Technology Letters},
year = {1991},
volume = {3},
number = {5},
pages = {430--432},
doi = {10.1109/68.93868}
}
|
| Chen JF, Yang L, Wu MC, Chu SNG and Cho AY (1990), "On the effect of the barrier widths in the InAs/AlSb/GaSb single‐barrier interband tunneling structures", Journal of Applied Physics., October, 1990. Vol. 68(7), pp. 3451-3455. |
| Abstract: The dependence of the interband tunneling current on AlSb barrier widths is studied in the InAs/AlSb/GaSb single‐barrier diode structures. The experimental results show that the peak current density displays an exponential dependence on the barrier width. The Wentzel‐Kramers‐Brillouin approximation combined with the k⋅p two‐band model were used in analyzing the energy level in the AlSb barrier through which the peak tunneling currents occur. The energy level thus obtained (0.48±0.10 eV above the valence band edge of the AlSb) agrees with the valence‐band offset (0.40±0.15 eV) between the AlSb and the GaSb obtained by x‐ray photoemissionmeasurement reported by Gualtieri e t a l. [Appl. Phys. Lett. 4 9, 1037 (1986)]. By adjusting the barrier width properly, we obtained a high peak current density of 24 kA/cm2 (with a peak‐to‐valley ratio of 1.4) and a high peak‐to‐valley ratio of 4.5 (with a peak current density of 3.5 kA/cm2) at room temperature. In addition, the peak‐current voltages for different AlSb barrier widths were calculated and compared with the measured results. |
BibTeX:
@article{chen_effect_1990,
author = {Chen, J. F. and Yang, L. and Wu, M. C. and Chu, S. N. G. and Cho, A. Y.},
title = {On the effect of the barrier widths in the InAs/AlSb/GaSb single‐barrier interband tunneling structures},
journal = {Journal of Applied Physics},
year = {1990},
volume = {68},
number = {7},
pages = {3451--3455},
url = {http://scitation.aip.org/content/aip/journal/jap/68/7/10.1063/1.346355},
doi = {10.1063/1.346355}
}
|
| Chen JF, Wu MC, Yang L and Cho AY (1990), "InAs/AlSb/GaSb single‐barrier interband tunneling diodes with high peak‐to‐valley ratios at room temperature", Journal of Applied Physics., September, 1990. Vol. 68(6), pp. 3040-3043. |
| Abstract: We have fabricated an InAs/AlSb/GaSb single‐barrier interband tunneling diode by molecular beam epitaxy. In this structure, a large tunneling current can be obtained by taking the advantage of the large heterojunction‐conduction band to valence band overlap (0.15 eV) between InAs and GaSb which offers flexible designs of the AlSb barrier thickness and the doping concentrations. We have obtained a negative differential resistance with a peak‐to‐valley current ratio as high as 4.7 and a peak current density of 3.5 kA/cm2 at room temperature with a 1.5‐nm‐thick AlSb barrier. The current transport mechanism in this tunneling structure will be discussed according to the I‐Vcharacteristics as a function of temperature. |
BibTeX:
@article{chen_inas/alsb/gasb_1990,
author = {Chen, J. F. and Wu, M. C. and Yang, L. and Cho, A. Y.},
title = {InAs/AlSb/GaSb single‐barrier interband tunneling diodes with high peak‐to‐valley ratios at room temperature},
journal = {Journal of Applied Physics},
year = {1990},
volume = {68},
number = {6},
pages = {3040--3043},
url = {http://scitation.aip.org/content/aip/journal/jap/68/6/10.1063/1.346396},
doi = {10.1063/1.346396}
}
|
| Tsang WT, Wu MC, Tanbun‐Ek T, Logan RA, Chu SNG and Sergent AM (1990), "Low threshold and high power output 1.5 μm InGaAs/InGaAsP separate confinement multiple quantum well laser grown by chemical beam epitaxy", Applied Physics Letters., November, 1990. Vol. 57(20), pp. 2065-2067. |
| Abstract: We have demonstrated the first successful preparation of InGaAs/InGaAsP multiple quantum well(MQW) lasers grown by chemical beam epitaxy. The broad‐area threshold current densities of standard (not graded index) separate confinement heterostructure (SCH) MQW lasers were as low as 860 and ∼590 A/cm2 for cavity lengths of 500 and 1500–3500 μm. Such values are similar to those obtained from MQW wafers employing the more advanced graded index SCH(GRIN‐SCH) grown by metalorganic vapor phase epitaxy. Buried‐heterostructure lasers also have similar threshold currents, i.e., 25–40 mA for 300–1500 long cavities. Pulsed and cw output power at 1.57 μm as high as 216 and 140 mW were obtained from 1‐mm‐long buried‐heterostructure lasers having antireflection and high reflection coatings of ∼5% and ∼85 The layer thickness uniformity is better than ±1% across a 2‐in.‐diam wafer. |
BibTeX:
@article{tsang_low_1990,
author = {Tsang, W. T. and Wu, M. C. and Tanbun‐Ek, T. and Logan, R. A. and Chu, S. N. G. and Sergent, A. M.},
title = {Low threshold and high power output 1.5 μm InGaAs/InGaAsP separate confinement multiple quantum well laser grown by chemical beam epitaxy},
journal = {Applied Physics Letters},
year = {1990},
volume = {57},
number = {20},
pages = {2065--2067},
url = {http://scitation.aip.org/content/aip/journal/apl/57/20/10.1063/1.103942},
doi = {10.1063/1.103942}
}
|
| Tsang W, Wu M, Yang L, Chen Y-K and Sergent A (1990), "Strained-layer 1.5um wavelength InGaAs/InP multiple quantum well lasers grown by chemical beam epitaxy", Electronics Letters., November, 1990. Vol. 26(24), pp. 2035-2036. |
| Abstract: A substantial reduction is reported in the threshold current densities for 1.5 mu m wavelength InxGa1-xAs/InxGa1-xAs1-yPy strained-layer multiple quantum well (SL-MQW) lasers over lattice-matched MQW lasers. Threshold current density was found to depend sensitively on the InAs content x and thickness d of the InxGa1-xAs quantum wells. Threshold current densities as low as 370 A/cm2 and internal quantum efficiency of 90% were obtained for separate confinement heterostructure Sl-MQW lasers having four quantum wells and with x=0.65 and d=5 nm. Such a threshold current density is among the lowest values obtained thus far for 1.5 mu m wavelength InGaAs/InGaAsP MQW lasers. The present lasers were grown by chemical beam epitaxy. |
BibTeX:
@article{tsang_strained-layer_1990,
author = {Tsang, W.T. and Wu, M.C. and Yang, L. and Chen, Y.-K. and Sergent, AM.},
title = {Strained-layer 1.5um wavelength InGaAs/InP multiple quantum well lasers grown by chemical beam epitaxy},
journal = {Electronics Letters},
year = {1990},
volume = {26},
number = {24},
pages = {2035--2036},
doi = {10.1049/el:19901313}
}
|
| Wu MC, Olsson NA, Sivco D and Cho AY (1990), "A 970 nm strained‐layer InGaAs/GaAlAs quantum well laser for pumping an erbium‐doped optical fiber amplifier", Applied Physics Letters., January, 1990. Vol. 56(3), pp. 221-223. |
| Abstract: We report the performance of a 970 nm strained‐layer InGaAs/GaAlAs quantum well laser and its application for pumping Er‐doped optical fiberamplifiers. The laser was grown by molecular beam epitaxy and has three In0.2Ga0.8As/GaAs quantum wells. For a 5‐μm‐wide and 400‐μm‐long ridge‐waveguide laser, a cw threshold current of 20 mA and an external quantum efficiency of 0.28 mW/mA per facet were obtained. Maximum output power exceeds 32 mW/facet. With antireflection coating, even higher external quantum efficiency (0.40 mW/mA) was achieved, and more than 20 mW of power was coupled into a single mode fiber. Preliminary experiments of pumping the Er‐doped fiber amplifier gave 15 dB of gain at 1.555 μm for a pump power of 14 mW into the Er fiber. |
BibTeX:
@article{wu_970_1990,
author = {Wu, Ming C. and Olsson, N. A. and Sivco, D. and Cho, A. Y.},
title = {A 970 nm strained‐layer InGaAs/GaAlAs quantum well laser for pumping an erbium‐doped optical fiber amplifier},
journal = {Applied Physics Letters},
year = {1990},
volume = {56},
number = {3},
pages = {221--223},
url = {http://scitation.aip.org/content/aip/journal/apl/56/3/10.1063/1.102837},
doi = {10.1063/1.102837}
}
|
| Wu MC, Yang L and Tsang WT (1990), "Quantum‐switched heterojunction bistable bipolar transistor by chemical beam epitaxy", Applied Physics Letters., July, 1990. Vol. 57(2), pp. 150-152. |
| Abstract: We proposed and demonstrated a novel bistable transistor−the quantum‐switched heterojunction bistable bipolar transistor. The transistor has two current states. With increasing base‐emitter voltage, the collector current is switched from high to low, while the base current is switched from low to high. Bistability is observed for a certain range of base voltage. This device has potential applications in implementing high‐speed single bipolar transistor memories, gain quenching in light‐emitting devices, and optoelectronic switching. |
BibTeX:
@article{wu_quantumswitched_1990,
author = {Wu, Ming C. and Yang, Long and Tsang, W. T.},
title = {Quantum‐switched heterojunction bistable bipolar transistor by chemical beam epitaxy},
journal = {Applied Physics Letters},
year = {1990},
volume = {57},
number = {2},
pages = {150--152},
url = {http://scitation.aip.org/content/aip/journal/apl/57/2/10.1063/1.103968},
doi = {10.1063/1.103968}
}
|
| Wu MC, Chen YK, Tanbun‐Ek T, Logan RA, Chin MA and Raybon G (1990), "Transform‐limited 1.4 ps optical pulses from a monolithic colliding‐pulse mode‐locked quantum well laser", Applied Physics Letters., August, 1990. Vol. 57(8), pp. 759-761. |
| Abstract: We report the generation of short optical pulses from novel monolithic colliding‐pulse mode‐locked quantum well lasers. Transform‐limited pulses with durations of 1.4 ps at a repetition rate of 32.6 GHz have been achieved, with nearly 100% intensity modulation depth and a peak optical power of 10 mW. This is the shortest transform‐limited pulse directly generated from monolithic mode‐locked lasers (time‐bandwidth product =0.3). |
BibTeX:
@article{wu_transformlimited_1990,
author = {Wu, M. C. and Chen, Y. K. and Tanbun‐Ek, T. and Logan, R. A. and Chin, M. A. and Raybon, G.},
title = {Transform‐limited 1.4 ps optical pulses from a monolithic colliding‐pulse mode‐locked quantum well laser},
journal = {Applied Physics Letters},
year = {1990},
volume = {57},
number = {8},
pages = {759--761},
url = {http://scitation.aip.org/content/aip/journal/apl/57/8/10.1063/1.103413},
doi = {10.1063/1.103413}
}
|
| Yang L, Wu MC, Tai K, Tanbun‐Ek T and Logan RA (1990), "InGaAsP(1.3 μm)/InP vertical‐cavity surface‐emitting laser grown by metalorganic vapor phase epitaxy", Applied Physics Letters., March, 1990. Vol. 56(10), pp. 889-891. |
| Abstract: We report InGaAsP/InP vertical‐cavity surface‐emitting lasers (VCSELs) with an emission wavelength near 1.3 μm grown by metalorganic vapor phase epitaxy. The VCSEL structure contains a double‐heterostructure cavity, a metal mirror, and a SiO2/Si dielectric stack (three pairs) mirror with a measuredreflectivity of 98 A threshold current as low as 5 mA for 15‐μm‐diam devices with a 1‐μm‐thick active layer at 77 K was achieved, which is close to the best reported value (6 mA) within the accuracy of the pulse measurement. The highest operating temperature was 220 K. |
BibTeX:
@article{yang_ingaasp1.3_1990,
author = {Yang, Long and Wu, Ming C. and Tai, Kuochou and Tanbun‐Ek, Tawee and Logan, Ralph A.},
title = {InGaAsP(1.3 μm)/InP vertical‐cavity surface‐emitting laser grown by metalorganic vapor phase epitaxy},
journal = {Applied Physics Letters},
year = {1990},
volume = {56},
number = {10},
pages = {889--891},
url = {http://scitation.aip.org/content/aip/journal/apl/56/10/10.1063/1.102619},
doi = {10.1063/1.102619}
}
|
| Yang L, Wu MC, Chen JF, Chen YK, Snider GL and Cho AY (1990), "Quantization effect on capacitance‐voltage and current‐voltage characteristics of an InAs/AlSb/GaSb interband tunneling diode", Journal of Applied Physics., October, 1990. Vol. 68(8), pp. 4286-4289. |
| Abstract: Capacitance‐voltage measurements were performed on the InAs/AlSb/GaSb interband tunneling diode at various frequencies. Theoretical analyses using a self‐consistent Schrödinger–Poisson solver were found in agreement with the experimental results under the forward‐bias condition. The quantization energy of each subband of the electron in the InAs accumulation region is used to predict the tunneling current cutoff voltage in agreement with that of the current‐voltage measurements. Therefore, the cutoff of the interband tunneling process is mainly caused by the crossover of the electron subband energy in the InAs conduction band with respect to the valence band of the GaSb electrode due to the increased external bias voltage. |
BibTeX:
@article{yang_quantization_1990,
author = {Yang, L. and Wu, M. C. and Chen, J. F. and Chen, Y. K. and Snider, G. L. and Cho, A. Y.},
title = {Quantization effect on capacitance‐voltage and current‐voltage characteristics of an InAs/AlSb/GaSb interband tunneling diode},
journal = {Journal of Applied Physics},
year = {1990},
volume = {68},
number = {8},
pages = {4286--4289},
url = {http://scitation.aip.org/content/aip/journal/jap/68/8/10.1063/1.346222},
doi = {10.1063/1.346222}
}
|
| Boenke M, Wu M, Wang S, Clark WM, Stevens E and Utlaut M (1989), "DBR laser with nondynamic plasma grating formed by focused ion beam implanted dopants", IEEE Journal of Quantum Electronics., June, 1989. Vol. 25(6), pp. 1294-1302. |
| Abstract: A static plasma grating has been demonstrated experimentally (see M.C. Wu et al., Appl. Phys. Lett., vol.53, no.4, p.265-7, 1988) in a large-optical-cavity focused-ion-beam-distributed-Bragg-reflector (FIB-DBR) GaAlAs/GaAs laser diode. The grating is formed by implanting stripes of dopants with a focused ion beam. The dopants ionize to form periodic fluctuations in the carrier concentration which, through the Kramers-Kronig relations, form an index grating. A model of the grating strength for optimization of the laser design is developed and presented. The computed results show that the coupling coefficient k can be increased by more than an order of magnitude over the 15 cm 1 experimentally. Therefore, FIB-DBR (or FIB-distributed-feedback (DFB)) lasers with performance comparable to that of conventional DBR (or DFB) lasers can be expected |
BibTeX:
@article{boenke_dbr_1989,
author = {Boenke, M.M. and Wu, M.C. and Wang, Shyh and Clark, William M. and Stevens, E.H. and Utlaut, M.W.},
title = {DBR laser with nondynamic plasma grating formed by focused ion beam implanted dopants},
journal = {IEEE Journal of Quantum Electronics},
year = {1989},
volume = {25},
number = {6},
pages = {1294--1302},
doi = {10.1109/3.29260}
}
|
| Wu MC and Tsang WT (1989), "Quantum‐switched heterojunction bipolar transistor", Applied Physics Letters., October, 1989. Vol. 55(17), pp. 1771-1773. |
| Abstract: We propose and demonstrate a negative differential resistance transistor—the quantum‐switched heterojunctionbipolar transistor (QSHBT). It has the highest current peak‐to‐valley ratio ever reported at r o o m t e m p e r a t u r e (15 in an InGaAs/InP QSHBT). More important, the switching and peak‐to‐valley ratio can be controlled by a base current injected electronically or optically. For example, a peak current as high as 72 mA or 2.9 kA/cm2 can be controlled by either a few microamperes of base current or a few microwatts of optical signal. A gain of peak current of 8650 at room temperature is obtained. The present device is grown by chemical beam epitaxy. |
BibTeX:
@article{wu_quantumswitched_1989,
author = {Wu, Ming C. and Tsang, W. T.},
title = {Quantum‐switched heterojunction bipolar transistor},
journal = {Applied Physics Letters},
year = {1989},
volume = {55},
number = {17},
pages = {1771--1773},
url = {http://scitation.aip.org/content/aip/journal/apl/55/17/10.1063/1.102214},
doi = {10.1063/1.102214}
}
|
| Zhu ZH, Lo YH, Wu MC, Pan CL, Wang SY, Gustafson TK and Wang S (1989), "Study of Electric Field Distribution in GaAs Materials and Devices Using Electro‐Optic Probing Technique", Journal of The Electrochemical Society., October, 1989. Vol. 136(10), pp. 3115-3123. |
| Abstract: Continuous wave (CW) and pulse electro‐optic probing techniques have been applied to study the electric field distribution in material and device. We have utilized the CW electro‐optic probing to measure the electric field profile of a coplanar waveguide made on a semi‐insulating substrate. This probing technique can be generalized to map out the three‐dimensional field distribution. In addition, the inhomogeneous distribution of deep levels in a liquid encapsulated Czochralski (LEC) semi‐insulating substrate is probed. The change of deep level concentration near the substrate surface after thermal annealing is in turn detected. Using the concept of harmonic mixing, we are able to employ the pulsed electro‐optic probing to measure the standing wave pattern in a coplanar waveguide with various terminations. This technique is demonstrated at microwave frequencies up to 20.10 GHz. The measured effective indexes of refraction are in good agreement with those predicted by theory. |
BibTeX:
@article{zhu_study_1989,
author = {Zhu, Z. H. and Lo, Y. H. and Wu, M. C. and Pan, C. L. and Wang, S. Y. and Gustafson, T. K. and Wang, S.},
title = {Study of Electric Field Distribution in GaAs Materials and Devices Using Electro‐Optic Probing Technique},
journal = {Journal of The Electrochemical Society},
year = {1989},
volume = {136},
number = {10},
pages = {3115--3123},
url = {http://jes.ecsdl.org/content/136/10/3115},
doi = {10.1149/1.2096411}
}
|
| Lo YH, Wu MC, Lee H, Wang S and Liliental‐Weber Z (1988), "Dislocation microstructures on flat and stepped Si surfaces: Guidance for growing high‐quality GaAs on (100) Si substrates", Applied Physics Letters., April, 1988. Vol. 52(17), pp. 1386-1388. |
| Abstract: Type‐I dislocations at the GaAs/Si interface are beneficial because they effectively relax the mismatched stress, but do not propagate into the GaAsfilm. Accordingly, the best way to grow a low defect density GaAsfilm on a Si substrate is to form as many as possible type‐I dislocations or, equivalently, to suppress other kinds of defects. The high‐resolution transmission electron microscopy study shows that most of the type‐I dislocations are formed at the double step on a Si surface. It is further determined that the silicon surface steps are mainly due to the substrate tilting instead of the heating before growth. Based on our study, the (100) Si substrate with double steps along both [110] and [11̄0] axes provides the best condition for growing low defect density GaAs on Si substrates. |
BibTeX:
@article{lo_dislocation_1988,
author = {Lo, Y. H. and Wu, M. C. and Lee, H. and Wang, S. and Liliental‐Weber, Z.},
title = {Dislocation microstructures on flat and stepped Si surfaces: Guidance for growing high‐quality GaAs on (100) Si substrates},
journal = {Applied Physics Letters},
year = {1988},
volume = {52},
number = {17},
pages = {1386--1388},
url = {http://scitation.aip.org/content/aip/journal/apl/52/17/10.1063/1.99124},
doi = {10.1063/1.99124}
}
|
| Vakhshoori D, Wu MC and Wang S (1988), "Surface‐emitting second‐harmonic generator for waveguide study", Applied Physics Letters., February, 1988. Vol. 52(6), pp. 422-424. |
| Abstract: A novel surface emission of coherently generated second‐harmonic wave is reported for the first time.The technique is used for the observation of the difference in propagation constant of the TE0 and TM0 mode of GaAs/AlGaAs waveguide cavity to a high degree of accuracy. In this technique the second‐harmonic signal propagates out from the top surface of the waveguide structure, converting the modal phase difference between TE0 and TM0 modes into intensity variation along the waveguide length. The second‐harmonic signal is easily observable by the naked eye, and the technique does not require wavelength tuning or mechanical movement for the measurement of birefringence. |
BibTeX:
@article{vakhshoori_surfaceemitting_1988,
author = {Vakhshoori, D. and Wu, M. C. and Wang, S.},
title = {Surface‐emitting second‐harmonic generator for waveguide study},
journal = {Applied Physics Letters},
year = {1988},
volume = {52},
number = {6},
pages = {422--424},
url = {http://scitation.aip.org/content/aip/journal/apl/52/6/10.1063/1.99430},
doi = {10.1063/1.99430}
}
|
| Wu MC, Boenke MM, Wang S, Jr WMC, Stevens EH and Utlaut MW (1988), "GaAs/GaAlAs distributed Bragg reflector laser with a focused ion beam, low dose dopant implanted grating", Applied Physics Letters., July, 1988. Vol. 53(4), pp. 265-267. |
| Abstract: We report for the first time, the performance of a GaAs/GaAlAs distributed Bragg reflector (DBR) laser using a focused ion beamimplantedgrating (FIB‐DBR). Stripes of Si+ + with a period of 2300 Å and a dose ∼101 4 cm− 2 are directly implanted into the passive large optical cavity layer to provide the distributed feedback. Surface‐emitting light from the second‐order grating is observed. Threshold current of 110 mA and single DBR mode operation from 20 to 40 °C are obtained. The wavelength tuning rate with temperature is 0.8 Å/°C. The coupling coefficient is estimated to be 15 cm− 1. The results show that FIBtechnology is practical for distributed feedback and DBR lasers and optoelectronic integrated circuits. |
BibTeX:
@article{wu_gaas/gaalas_1988,
author = {Wu, M. C. and Boenke, M. M. and Wang, S. and Jr, W. M. Clark and Stevens, E. H. and Utlaut, M. W.},
title = {GaAs/GaAlAs distributed Bragg reflector laser with a focused ion beam, low dose dopant implanted grating},
journal = {Applied Physics Letters},
year = {1988},
volume = {53},
number = {4},
pages = {265--267},
url = {http://scitation.aip.org/content/aip/journal/apl/53/4/10.1063/1.100142},
doi = {10.1063/1.100142}
}
|
| Wu M-C, Lo Y-h and Wang S (1988), "Linewidth broadening due to longitudinal spatial hole burning in a long distributed feedback laser", Applied Physics Letters., April, 1988. Vol. 52(14), pp. 1119-1121. |
| Abstract: The spectral linewidth of a long distributed feedback (DFB) laser above threshold at high output power is investigated theoretically. Longitudinal spatial hole burning (LSHB) is shown to have important effects on the lasing characteristics and the broadening of linewidth. A four‐wave coupled mode equation is developed to describe the LSHB phenomenon. The threshold gain and the carrier distribution are solved self‐consistently above threshold at various output powers. The simulation results show that the power‐linewidth product can increase by a factor greater than 2 due to LSHB for long DFB lasers. This theory has important implications on the limits of linewidth reduction by increasing the length of DFB lasers and on possible future device design for coherent optical system. |
BibTeX:
@article{wu_linewidth_1988,
author = {Wu, Ming-Chiang and Lo, Yu-hwa and Wang, Shyh},
title = {Linewidth broadening due to longitudinal spatial hole burning in a long distributed feedback laser},
journal = {Applied Physics Letters},
year = {1988},
volume = {52},
number = {14},
pages = {1119--1121},
url = {http://scitation.aip.org/content/aip/journal/apl/52/14/10.1063/1.99180},
doi = {10.1063/1.99180}
}
|
| Wu MC, Boenke MM, Werner M, Schiffmann F, Lo YH and Wang S (1988), "Wavelength tuning and switching of a coupled distributed feedback and Fabry–Perot cavity laser", Journal of Applied Physics., January, 1988. Vol. 63(2), pp. 291-294. |
| Abstract: We present a theoretical analysis of a newly demonstrated semiconductor laser with coupled distributed feedback and Fabry–Perot (DFB‐FP) cavities and show that three modes of operation are possible for such a laser. In mode‐switched DFB mode, the wavelength can be switched between longitudinal modes on either side of the stopband. In coupled‐cavity laser mode, there are successive mode hops inside the stopband. Finally, in continuously tunable distributed Bragg reflector mode, a wide wavelength tuning range (4.8 Å) without mode hopping can be obtained. The analysis is general enough to be applied to any laser with a periodic waveguide section, and provides an understanding of the mechanisms and the limits of wavelength tuning in such lasers. This type of laser has very important applications in coherent optical communications. |
BibTeX:
@article{wu_wavelength_1988,
author = {Wu, M. C. and Boenke, M. M. and Werner, M. and Schiffmann, F. and Lo, Y. H. and Wang, S.},
title = {Wavelength tuning and switching of a coupled distributed feedback and Fabry–Perot cavity laser},
journal = {Journal of Applied Physics},
year = {1988},
volume = {63},
number = {2},
pages = {291--294},
url = {http://scitation.aip.org/content/aip/journal/jap/63/2/10.1063/1.340292},
doi = {10.1063/1.340292}
}
|
| Zhu ZH, Wu MC, Lo YH, Pan CL, Wang SY and Wang S (1988), "Measurements on standing waves in GaAs coplanar waveguide at frequencies up to 20.1 GHz by electro‐optic probing", Journal of Applied Physics., July, 1988. Vol. 64(1), pp. 419-421. |
| Abstract: We report the experimental results of the standing waves in GaAs coplanar waveguides at frequencies up to 20.10 GHz with different terminations (open, short, and 50 Ω) by a new electro‐optic probing technique. The effective refractive indices from 4.11 to 20.10 GHz are presented and compared with theoretical values. Dispersion of coplanar waveguide in that frequency range is shown to be negligible. |
BibTeX:
@article{zhu_measurements_1988,
author = {Zhu, Z. H. and Wu, M. C. and Lo, Y. H. and Pan, C. L. and Wang, S. Y. and Wang, S.},
title = {Measurements on standing waves in GaAs coplanar waveguide at frequencies up to 20.1 GHz by electro‐optic probing},
journal = {Journal of Applied Physics},
year = {1988},
volume = {64},
number = {1},
pages = {419--421},
url = {http://scitation.aip.org/content/aip/journal/jap/64/1/10.1063/1.341444},
doi = {10.1063/1.341444}
}
|
| Hong JM, Wu MC, Wang S, Wang WI and Chang LL (1987), "GaAs‐GaAlAs graded‐index separate confinement heterostructure laser diodes selectively grown by molecular beam epitaxy on SiO2‐masked substrates", Applied Physics Letters., September, 1987. Vol. 51(12), pp. 886-888. |
| Abstract: The GaAs‐GaAlAs graded‐index separate confinement heterostructure was grown selectively by molecular beam epitaxy on a SiO2‐masked GaAs (100) substrate. The stripe windows on the SiO2 mask were 10 μm in width and were oriented along [011̄] direction. The laser diodes thus fabricated lased in a single longitudinal mode with a side mode suppression ratio of 95:1. Both the longitudinal mode and the single‐lobe far‐field pattern were stable up to 4I th. |
BibTeX:
@article{hong_gaasgaalas_1987,
author = {Hong, J. M. and Wu, M. C. and Wang, S. and Wang, W. I. and Chang, L. L.},
title = {GaAs‐GaAlAs graded‐index separate confinement heterostructure laser diodes selectively grown by molecular beam epitaxy on SiO2‐masked substrates},
journal = {Applied Physics Letters},
year = {1987},
volume = {51},
number = {12},
pages = {886--888},
url = {http://scitation.aip.org/content/aip/journal/apl/51/12/10.1063/1.98844},
doi = {10.1063/1.98844}
}
|
| Lo YH, Wu MC, Zhu ZH, Wang SY and Wang S (1987), "Proposal for three‐dimensional internal field mapping by cw electro‐optic probing", Applied Physics Letters., June, 1987. Vol. 50(25), pp. 1791-1793. |
| Abstract: The cw electro‐optic probing technique is for the first time proposed to detect the three‐dimensional internal field distribution in linear electro‐optic material like GaAs. By changing the incident angles and positions of the probing beam, sufficient information of the electric field distribution is included in the phase retardation of the probing beam. If certain conditions on the probing beam are satisfied, a very simple linear relation between phase retardation and each field component can be found and the whole problem becomes not only mathematically solvable but experimentally feasible. Finally, a three‐dimensional computer simulation is undertaken to illustrate the relation between field distribution and detected electro‐optic signal. |
BibTeX:
@article{lo_proposal_1987,
author = {Lo, Y. H. and Wu, M. C. and Zhu, Z. H. and Wang, S. Y. and Wang, S.},
title = {Proposal for three‐dimensional internal field mapping by cw electro‐optic probing},
journal = {Applied Physics Letters},
year = {1987},
volume = {50},
number = {25},
pages = {1791--1793},
url = {http://scitation.aip.org/content/aip/journal/apl/50/25/10.1063/1.97698},
doi = {10.1063/1.97698}
}
|
| Ogura M, Wu M-c, Hsin W, Whinnery JR and Wang S (1987), "Surface emitting laser diode with bent waveguide", Applied Physics Letters., March, 1987. Vol. 50(12), pp. 705-707. |
| Abstract: A surface emitting laserdiode (SELD) with a bent double heterostructure is fabricated on a grooved substrate. This SELD has a facet angle of 20 ° and lased at a threshold current of 120 mA. The external quantum efficiency is 33 The far‐field pattern has sharp peaks at 10 ° and 18 ° and wider emission bands between 25 ° and 45 °. Radiation loss by the bent waveguide is also estimated by the equivalent current source model. |
BibTeX:
@article{ogura_surface_1987,
author = {Ogura, Mutsuo and Wu, Ming-chiang and Hsin, Wei and Whinnery, John R. and Wang, Shyh},
title = {Surface emitting laser diode with bent waveguide},
journal = {Applied Physics Letters},
year = {1987},
volume = {50},
number = {12},
pages = {705--707},
url = {http://scitation.aip.org/content/aip/journal/apl/50/12/10.1063/1.98073},
doi = {10.1063/1.98073}
}
|
| Ogura M, Hsin W, Wu M-C, Wang S, Whinnery JR, Wang SC and Yang JJ (1987), "Surface‐emitting laser diode with vertical GaAs/GaAlAs quarter‐wavelength multilayers and lateral buried heterostructure", Applied Physics Letters., November, 1987. Vol. 51(21), pp. 1655-1657. |
| Abstract: Threshold current of 2 mA at room temperature cw operation is realized in a vertical distributed feedback surface‐emitting laser diode with lateral buried heterostructure (LBH). In this LBH structure, the vertical distributed feedback active region (AlGaAs/GaAs multilayer) is entirely surrounded with n‐ and p‐type AlGaAs cladding layers for minority‐carrier confinement. The far‐field angle is 7°. The beam shape is nearly circular. However, the lasing spectrum is broad (2–3 nm) compared with the conventional edge‐emitting laser. Major differences between the surface‐emitting laser diode presented here and the conventional edge‐emitting laser diode are discussed. |
BibTeX:
@article{ogura_surfaceemitting_1987,
author = {Ogura, Mutsuo and Hsin, Wei and Wu, Ming-Chiang and Wang, Shyh and Whinnery, John R. and Wang, S. C. and Yang, Jane J.},
title = {Surface‐emitting laser diode with vertical GaAs/GaAlAs quarter‐wavelength multilayers and lateral buried heterostructure},
journal = {Applied Physics Letters},
year = {1987},
volume = {51},
number = {21},
pages = {1655--1657},
url = {http://scitation.aip.org/content/aip/journal/apl/51/21/10.1063/1.98586},
doi = {10.1063/1.98586}
}
|
| Zhu ZH, Pan CL, Lo YH, Wu MC, Wang S, Kolner BH and Wang SY (1987), "Electro‐optic measurement of standing waves in a GaAs coplanar waveguide", Applied Physics Letters., May, 1987. Vol. 50(18), pp. 1228-1230. |
| Abstract: We have successfully measured, for the first time, standing waves in a GaAs coplanar waveguide at frequencies of 8.2107 and 12.310 GHz by using harmonic‐mixing electro‐optic probing. The technique is nondestructive and has great potential in expanding the measuring frequency band to millimeter wave. This letter describes the principle of the technique, the experimental setup, and the measurement results. |
BibTeX:
@article{zhu_electrooptic_1987,
author = {Zhu, Z. H. and Pan, C. L. and Lo, Y. H. and Wu, M. C. and Wang, S. and Kolner, B. H. and Wang, S. Y.},
title = {Electro‐optic measurement of standing waves in a GaAs coplanar waveguide},
journal = {Applied Physics Letters},
year = {1987},
volume = {50},
number = {18},
pages = {1228--1230},
url = {http://scitation.aip.org/content/aip/journal/apl/50/18/10.1063/1.97917},
doi = {10.1063/1.97917}
}
|
| Lo YH, Hong J, Wu M and Wang S (1986), "The transport and isolation properties of polycrystalline GaAs selectively grown by molecular beam epitaxy", IEEE Electron Device Letters., October, 1986. Vol. 7(10), pp. 586-588. |
| Abstract: Selective-area polycrystalline GaAs using SiO2masking is planarly grown by molecular beam epitaxy (MBE). The electric properties of the polycrystalline GaAs are investigated because this technology is very promising for device isolation in GaAs integrated circuit and electro-optic integration. Compared with the isolation characteristics of semi-insulating GaAs, polycrystalline GaAs has similar low-field resistivity, higher high-field leakage current, and no well-defined trap-fill-limited voltage. The grain boundary (GB) states of polycrystalline GaAs trap negative charge that builds up a potential barrier to hinder electron current. The GB density of states profile estimated from the IV characteristics shows a peak value 5 × 1012cm-2.eV1and a wide energy distribution, 0.33 eV above the equilibrium Fermi energy. |
BibTeX:
@article{lo_transport_1986,
author = {Lo, Y. -H and Hong, J. and Wu, M.C. and Wang, Syhy},
title = {The transport and isolation properties of polycrystalline GaAs selectively grown by molecular beam epitaxy},
journal = {IEEE Electron Device Letters},
year = {1986},
volume = {7},
number = {10},
pages = {586--588},
doi = {10.1109/EDL.1986.26482}
}
|