Yahsing Yuan | University of Michigan (original) (raw)
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Papers by Yahsing Yuan
SPIE Proceedings, 1997
The performance characteristics of an integrated InGaAsP/InP laser-modulator made by one step epi... more The performance characteristics of an integrated InGaAsP/InP laser-modulator made by one step epitaxy and well-controlled reactive ion etching (RIE) have been analyzed and measured. A theoretical model based on a finite-difference time domain (FDTD) technique was used to simulate the propagation of a optical wave launched in the coupled system and determine the reflectivity of the facets created by RIE. The calculated effective reflectivity of the coupling region consisting of two facets and an air gap in between is 0.55, which is in a good agreement with the experimentally measured value of 0.5. The reflectivity of a single etched mirror derived from this value is estimated to be 0.3. A 120 micrometer long integrated modulator excited by the laser shows a maximum extinction ratio of 8 dB and a modulation bandwidth greater than or equal to 14 GHz at a dc bias of minus 0.5 V with a bias swing of 2 V. This is comparable to the best results reported for an integrated modulator.
![Research paper thumbnail of Monolithically Integrated Transmitters for 1.5 [mu] m Optical Communication Applications](https://attachments.academia-assets.com/31166810/thumbnails/1.jpg)
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Optoelectronics …, 1998
To circumvent the numerous performance-limiting effects of hot-carrier phenomena in semiconductor... more To circumvent the numerous performance-limiting effects of hot-carrier phenomena in semiconductor quantumwell lasers, we have demonstrated the innovative approach of directly injecting carriers into the lasing subband by tunneling. These lasers, made with a variety of material systems, have shown evidence of reduced hot-carrier effects. Specifically, measured small-signal modulation bandwidth of 5O GHz and maximum intrinsic bandwidth of 1 10 GHz have been achieved with 0.98 j.tm lasers. These are the highest measured modulation bandwidths in any laser. Auger recombination has been virtually eliminated in 1 .55 j.tm lasers and reduced chirp and temperature dependence are also demonstrated. Significant reduction of hot-carrier and carrier leakage effects have also been recently demonstrated in small-area vertical-cavity surface-emitting lasers. These experimental results are supported by recent simulations that identify gain suppression in high speed lasers to be caused by a coupling between the electron temperature and the quasi Fermi level.
SPIE Proceedings, 1997
The performance characteristics of an integrated InGaAsP/InP laser-modulator made by one step epi... more The performance characteristics of an integrated InGaAsP/InP laser-modulator made by one step epitaxy and well-controlled reactive ion etching (RIE) have been analyzed and measured. A theoretical model based on a finite-difference time domain (FDTD) technique was used to simulate the propagation of a optical wave launched in the coupled system and determine the reflectivity of the facets created by RIE. The calculated effective reflectivity of the coupling region consisting of two facets and an air gap in between is 0.55, which is in a good agreement with the experimentally measured value of 0.5. The reflectivity of a single etched mirror derived from this value is estimated to be 0.3. A 120 micrometer long integrated modulator excited by the laser shows a maximum extinction ratio of 8 dB and a modulation bandwidth greater than or equal to 14 GHz at a dc bias of minus 0.5 V with a bias swing of 2 V. This is comparable to the best results reported for an integrated modulator.
Optoelectronics …, 1998
To circumvent the numerous performance-limiting effects of hot-carrier phenomena in semiconductor... more To circumvent the numerous performance-limiting effects of hot-carrier phenomena in semiconductor quantumwell lasers, we have demonstrated the innovative approach of directly injecting carriers into the lasing subband by tunneling. These lasers, made with a variety of material systems, have shown evidence of reduced hot-carrier effects. Specifically, measured small-signal modulation bandwidth of 5O GHz and maximum intrinsic bandwidth of 1 10 GHz have been achieved with 0.98 j.tm lasers. These are the highest measured modulation bandwidths in any laser. Auger recombination has been virtually eliminated in 1 .55 j.tm lasers and reduced chirp and temperature dependence are also demonstrated. Significant reduction of hot-carrier and carrier leakage effects have also been recently demonstrated in small-area vertical-cavity surface-emitting lasers. These experimental results are supported by recent simulations that identify gain suppression in high speed lasers to be caused by a coupling between the electron temperature and the quasi Fermi level.