Browsing by Author "Chyi, J. -I."

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Bandwidth enhancement phenomenon of a high-speed GaAs-AlGaAs based unitraveling carrier photodiode with an optimally designed absorption layer at an 830 nm wavelength
(2006-07-31)
Shi, Jin-Wei
;
Li, Yu-Tai
;
Pan, Ci-Ling
;
Lin, M. L.
;
Wu, Y. S.
In this letter, the authors introduce a GaAs/AlGaAs based unitraveling carrier photodiode (UTC-PD) for a wavelength of around 830 nm. There is significant bias- and output-current-dependent bandwidth enhancement phenomena observed with this device. According to their microwave and optical-to-electrical measurement results, such distinct phenomena can occur under a much lower current density (0.3 mA/mu m(2) vs 0.05 mA/mu m(2)) than previously reported for InP-InGaAs UTC-PDs. This can be attributed to the self-induced field in the absorption region, made possible due to the optimized p-type doping profile. (c) 2006 American Institute of Physics.
Characterization of a Sub-THz Photonic Transmitter Based on a Sep arated-Tran sp o rt-Recombin ation Photodiode
(2007)
Shi, J. -W.
;
Li, Yu-Tai
;
Pan, Ci-Ling
;
Chiu, C. -H.
;
Liu, W. -S.
By incorporating low-temperature-grown GaAs based separated-transport-recombination photodiode with micromachined antenna, such photonic-transmitter can radiate strong sub-THz waves at designed frequency (similar to 500GHz) without using Si-lens. Problems of device saturation under high bias voltage were also eliminated. (C) 2005 Optical Society of America
Distinct Dynamic Behaviors of High-Power Photonic-Transmitters Based on Uni-Traveling Carrier and Separated-Transport-Recombination Photodiodes
(2009)
Li, Yu-Tai
;
Yang, Chan-Shan
;
Pan, Ci-Ling
;
Shi, J. -W.
;
Huang, C. -Y.
We demonstrate two high-performance photonic-transmitters based on uni-traveling-carrier-photodiode (UTC-PD) and separated-transport-recombination-photodiode (STR-PD). Thanks to recombination center, STR-PD exhibits comparable maximum-peak-power and electrical pulse-width with much smaller photocurrents and less serious device-heating to those of UTC-PD.
Phosphor-free GaN-based transverse junction light emitting diodes for the generation of white light
(2006-11-01)
Shi, J. -W.
;
Huang, H. -Y
;
Wang, C. -K.
;
Sheu, J. -K.
;
Lai, W. -C.
We demonstrate a GaN-based phosphor-free near-white-light light-emitting-diode (LED) structure that operates in the visible wavelengths and offers broadening and flattening optical bandwidth performance. The incorporation of GaN-based dual wavelengths (blue and green) multiple-quantum-wells with a transverse p-n junction produces a device which can directly generate stable and near visible white-light emissions. The shape of the optical spectra (440-560 nm) are invariable from low to very high levels of bias currents. The problems of nonuniform carrier distribution and bias dependent electrolumineseence. spectra that occur in traditional phosphor-free white-light or near-white-light LEDs (with vertical p-n junctions) are eliminated by the demonstrated structure.
Sub-THz Photonic-Transmitters Based on GaAs/AlGaAs Uni-Traveling Carrier Photodiode and Micromachined Circular Disk Monopole Antenna for Ultra-wideband Communication
(2008)
Li, Yu-Tai
;
Pan, Ci-Ling
;
Shi, J. -W.
;
Huang, Cheng-Yu
;
Chen, Nan-Wei
By incorporating GaAs/AlGaAs based uni-traveling-carrier photodiodes with broadband micromachined monopole antennas, the demonstrated photonic-transmitter can radiate strong sub-THz pulses (20mW peak-power) with a wide bandwidth (100 similar to 250GHz), which was measured by another photonic-receiver for ultra-wideband communication. (c) 2008 Optical Society of America