The Experts below are selected from a list of 36072 Experts worldwide ranked by ideXlab platform
Hon Ki Tsang - One of the best experts on this subject based on the ideXlab platform.
-
investigation of 4 ask Modulation with digital filtering to increase 20 times of direct Modulation Speed of white light led visible light communication system
Optics Express, 2012Co-Authors: Chienhung Yeh, Y F Liu, Chiwai Chow, Yang Liu, P Y Huang, Hon Ki TsangAbstract:In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) Modulation with digital filtering to enhance the direct Modulation Speed of white-light light-emitting-diode (LED) in visible light communication (VLC) system. Here, an ordinary LED commercially available for lighting application with a direct Modulation Speed of 1 MHz is used. Data rate of 20 Mbit/s can be achieved in a 1 m free space transmission without using optical blue filter. In the previous studies, the transmission rate of LED VLC could only be increased by 2 to 10 times of the direct Modulation Speed of the white-light LED if using electrical equalization only. Moreover, the adaptive-controlled FIR filter makes the system closer to the matched filtering condition for reducing the inter-symbol-interference (ISI) for the LED VLC. A recorded 20 times enhancement of the direct Modulation Speed of white-light LED VLC system is demonstrated by using digital filter only and without using optical blue filter.
-
investigation of 4 ask Modulation with digital filtering to increase 20 times of direct Modulation Speed of white light led visible light communication system
Optics Express, 2012Co-Authors: C W Chow, P Y Huang, Hon Ki TsangAbstract:In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) Modulation with digital filtering to enhance the direct Modulation Speed of white-light light-emitting-diode (LED) in visible light communication (VLC) system. Here, an ordinary LED commercially available for lighting application with a direct Modulation Speed of 1 MHz is used. Data rate of 20 Mbit/s can be achieved in a 1 m free space transmission without using optical blue filter. In the previous studies, the transmission rate of LED VLC could only be increased by 2 to 10 times of the direct Modulation Speed of the white-light LED if using electrical equalization only. Moreover, the adaptive-controlled FIR filter makes the system closer to the matched filtering condition for reducing the inter-symbol-interference (ISI) for the LED VLC. A recorded 20 times enhancement of the direct Modulation Speed of white-light LED VLC system is demonstrated by using digital filter only and without using optical blue filter.
Jinnkong Sheu - One of the best experts on this subject based on the ideXlab platform.
-
iii nitride based cyan light emitting diodes with ghz bandwidth for high Speed visible light communication
IEEE Electron Device Letters, 2016Co-Authors: John E Bowers, Yahsuan Shih, Jinnkong SheuAbstract:A large reduction (from 17 to 5 nm) is made in the thickness of the barrier layers in the multiple-quantum-well region of III-nitride-based cyan light-emitting diodes (LEDs) grown on patterned sapphire substrates. This is shown to lead to a simultaneous improvement in the Modulation Speed, differential quantum efficiency, and maximum output power of the LEDs under both room temperature and 110 °C operation. With our novel device structure, we achieve a moderate output power (1.7 mW) with a record high 3-dB electrical-to-optical (E-O) bandwidth (1 GHz). The over twofold enhancement in the E-O bandwidth ( $\sim 1$ versus $\sim 0.5$ GHz) compared with that previously reported visible LEDs can be attributed to the more uniform distribution of injected carriers within the MQW region and the aggressive downscaling of the thickness of the total active layer, which leads to a shortening of the spontaneous recombination time.
-
very high temperature 200 c operation of gan based cascade green light emitting diode for plastic optical fiber communication
Optical Fiber Communication Conference, 2010Co-Authors: Jin-wei Shi, F M Kuo, H W Huang, M L Lee, Jinnkong SheuAbstract:We demonstrate cascade green light-emitting-diodes, which greatly release trade-off between output-power and Speed and exhibits strong Modulation-Speed enhancement with negligible output-power degradation from room-temperature to 200°C operation. 200Mbit/sec error-free transmission at 200°C can be achieved.
-
the improvement in Modulation Speed of gan based green light emitting diode led by use of n type barrier doping for plastic optical fiber pof communication
IEEE Photonics Technology Letters, 2006Co-Authors: Jin-wei Shi, H Y Huang, Y S Wu, Jinnkong Sheu, C H Chen, W C LaiAbstract:We demonstrate a high-Speed GaN-based light-emitting diode at a wavelength of around 500 nm for the application to plastic optical fiber communication. By use of the n-type doping in the GaN barrier layers of the InxGa1-xN-GaN-based multiple-quantum-well (MQW), superior performance of Modulation-Speed (120 versus 40 MHz) and output power to the undoped control under the same bias current has been observed. According to the measured electrical-to-optical bandwidths and extracted RC-limited bandwidths of both devices, the superior Speed performance can be attributed to higher electron/hole radiative recombination rate in the n-doped MQW than that of undoped MQW
-
Modulation Speed enhancement of a gan based green light emitting diode led by use of n type barrier doping for plastic optical fiber pof communication
Quantum Electronics and Laser Science Conference, 2006Co-Authors: H Y Huang, Jin-wei Shi, J I Chyi, Y S Wu, Jinnkong Sheu, W C Lai, Gongru Lin, Ciling PanAbstract:We demonstrate a high-Speed green GaN light-emitting-diode for plastic optical fiber communication. By use of n-type doping in barrier layers, superior performance of Modulation-Speed and output-power to undoped control has been observed.
Jin-wei Shi - One of the best experts on this subject based on the ideXlab platform.
-
very high bit rate distance product using high power single mode 850 nm vcsel with discrete multitone Modulation formats through om4 multimode fiber
IEEE Journal of Selected Topics in Quantum Electronics, 2015Co-Authors: Chiachien Wei, Jin-wei Shi, Hsingyu Chen, Kuanzhou Chen, Chenghsiang Huang, Kailun Chi, Fani Lai, Danhua Hsieh, Haochung Kuo, Wei LinAbstract:In order to investigate the tradeoff between optical spectral width and Modulation Speed of 850-nm Zn-diffusion vertical-cavity surface-emitting laser (VCSEL) and its influence on the performance of discrete multitone (DMT) Modulation, two kinds of high-Speed VCSEL structures with different cavity lengths (λ/2 and 3λ/2) are studied. By shortening the cavity length to λ/2, allocating the oxide layer in the standing-wave peak, and performing a Zn-diffusion aperture in our VCSEL structure, stable dual mode in the output optical spectra across the full range of bias currents with good high-Speed performance (∼16-GHz bandwidth) can be achieved. Compared with its multimode reference, it shows far less roll-off with regard to the maximum data rate versus transmission distance over OM4 multimode fibers under forward error correction (FEC) threshold (BER $ ). On the other hand, for the 3λ/2 VCSEL structure, by using the same Zn-diffusion conditions as those of dual-mode counterpart, highly single-mode operation (side-mode suppression ratio> 35 dB) with high available power can be achieved over the full range of bias currents. Although such device shows a smaller 3-dB electrical-to-optical bandwidth (12 versus 16 GHz) than that of the dual-mode one, it exhibits a superior transmission performance by use of DMT Modulation format. A record high bit-rate distance product (107.6 Gb/s·km) at nearly 50-Gb/s transmission under FEC threshold (BER $ ) through 2.2-km OM4 fibers has been successfully demonstrated by the use of single-mode VCSEL with optimized structures. In addition, error-free (BER $ ) transmission at 20.3 Gb/s with bit-rate distance product of 44.66 Gb/s·km has also been demonstrated.
-
oxide relief vertical cavity surface emitting lasers with extremely high data rate power dissipation ratios
Optical Fiber Communication Conference, 2011Co-Authors: Jin-wei Shi, W C Weng, F M Kuo, J I Chyi, S Pinches, M Geen, A JoelAbstract:By using oxide-relief technique, a high Modulation-efficiency (9.8GHz/mA1/2) and a high Modulation-Speed (34 Gbps) with a record-high data-rate/power-dissipation ratios (2.9 (9.2) Gbps/mW at 34 (12.5) Gbps) of 850nm VCSELs have been demonstrated.
-
very high temperature 200 c operation of gan based cascade green light emitting diode for plastic optical fiber communication
Optical Fiber Communication Conference, 2010Co-Authors: Jin-wei Shi, F M Kuo, H W Huang, M L Lee, Jinnkong SheuAbstract:We demonstrate cascade green light-emitting-diodes, which greatly release trade-off between output-power and Speed and exhibits strong Modulation-Speed enhancement with negligible output-power degradation from room-temperature to 200°C operation. 200Mbit/sec error-free transmission at 200°C can be achieved.
-
the improvement in Modulation Speed of gan based green light emitting diode led by use of n type barrier doping for plastic optical fiber pof communication
IEEE Photonics Technology Letters, 2006Co-Authors: Jin-wei Shi, H Y Huang, Y S Wu, Jinnkong Sheu, C H Chen, W C LaiAbstract:We demonstrate a high-Speed GaN-based light-emitting diode at a wavelength of around 500 nm for the application to plastic optical fiber communication. By use of the n-type doping in the GaN barrier layers of the InxGa1-xN-GaN-based multiple-quantum-well (MQW), superior performance of Modulation-Speed (120 versus 40 MHz) and output power to the undoped control under the same bias current has been observed. According to the measured electrical-to-optical bandwidths and extracted RC-limited bandwidths of both devices, the superior Speed performance can be attributed to higher electron/hole radiative recombination rate in the n-doped MQW than that of undoped MQW
-
Modulation Speed enhancement of a gan based green light emitting diode led by use of n type barrier doping for plastic optical fiber pof communication
Quantum Electronics and Laser Science Conference, 2006Co-Authors: H Y Huang, Jin-wei Shi, J I Chyi, Y S Wu, Jinnkong Sheu, W C Lai, Gongru Lin, Ciling PanAbstract:We demonstrate a high-Speed green GaN light-emitting-diode for plastic optical fiber communication. By use of n-type doping in barrier layers, superior performance of Modulation-Speed and output-power to undoped control has been observed.
R Bhat - One of the best experts on this subject based on the ideXlab platform.
-
high power high Modulation Speed 1060 nm dbr lasers for green light emission
IEEE Photonics Technology Letters, 2006Co-Authors: Hong Ky Nguyen, Sean Coleman, Nick Visovsky, Kechang Song, Xingsheng Liu, Nobuhiko Nishiyama, Lawrence C Hughes, Jacques Gollier, William James Miller, R BhatAbstract:We report on the static and dynamic performance of high-power and high-Modulation-Speed 1060-nm distributed Bragg reflector (DBR) lasers for green-light emission by second-harmonic generation. Single-wavelength power of 387 mW at 1060-nm wavelength and green power as high as 99.5 mW were achieved. A thermally induced wavelength tuning of 2.4 nm and a carrier-induced wavelength tuning of -0.85 nm were obtained by injecting current into the DBR section. Measured rise-fall times of 0.2 ns for direct intensity Modulation and 0.6 ns for wavelength Modulation make the lasers suitable for >50-MHz green-light Modulation applications
-
high performance uncooled 1 3 spl mu m al sub x ga sub y in sub 1 x y as inp strained layer quantum well lasers for subscriber loop applications
IEEE Journal of Quantum Electronics, 1994Co-Authors: R Bhat, B Pathak, F Favire, M C Wang, N C Andreadakis, D M Hwang, M A Koza, Z Wang, D Darby, D FlandersAbstract:Design considerations for fabricating highly efficient uncooled semiconductor lasers are discussed. The parameters investigated include the temperature characteristics of threshold current, quantum efficiency, and Modulation Speed. To prevent carrier overflow under high-temperature operation, the electron confinement energy is increased by using the Al/sub x/Ga/sub y/In/sub 1-x-y/As/InP material system instead of the conventional Ga/sub x/In/sub 1-x/As/sub y/P/sub 1-y//InP material system. To reduce the transparency current and the carrier-density-dependent loss due to the intervalence-band absorption, strained-layer quantum wells are chosen as the active layer. Experimentally, 1.3-/spl mu/m compressive-strained five-quantum-well lasers and tensile-strained three-quantum-well lasers were fabricated using a 3-/spl mu/m wide ridge-waveguide laser structure. For both types of lasers, the intrinsic material parameters are found to be similar in magnitude and in temperature dependence if they are normalized to each well. Specifically, the compressive-strained five-quantum-well lasers show excellent extrinsic temperature characteristics, such as small drop of 0.3 dB in differential quantum efficiency when the heat sink temperature changes from 25 to 100/spl deg/C, and a large small-signal Modulation bandwidth of 8.6 GHz at 85/spl deg/C. The maximum 3 dB Modulation bandwidth was measured to be 19.6 GHz for compressive-strained lasers and 17 GHz for tensile-strained-lasers by an optical Modulation technique. The strong carrier confinement also results in a small k-factor (0.25 ns) which indicates the potential for high-Speed Modulation up to 35 GHz. In spite of the aluminum-containing active layer, no catastrophic optical damage was observed at room temperature up to 218 mW for compressive-strained five-quantum-well lasers and 103 mW for tensile-strained three-quantum-well lasers. For operating the compressive-strained five-quantum-well lasers at 85/spl deg/C with more than 5 mW output power, a mean-time-to-failure (MTTF) of 9.4 years is projected from a preliminary life test. These lasers are highly attractive for uncooled, potentially low-cost applications in the subscriber loop. >
W C Lai - One of the best experts on this subject based on the ideXlab platform.
-
the improvement in Modulation Speed of gan based green light emitting diode led by use of n type barrier doping for plastic optical fiber pof communication
IEEE Photonics Technology Letters, 2006Co-Authors: Jin-wei Shi, H Y Huang, Y S Wu, Jinnkong Sheu, C H Chen, W C LaiAbstract:We demonstrate a high-Speed GaN-based light-emitting diode at a wavelength of around 500 nm for the application to plastic optical fiber communication. By use of the n-type doping in the GaN barrier layers of the InxGa1-xN-GaN-based multiple-quantum-well (MQW), superior performance of Modulation-Speed (120 versus 40 MHz) and output power to the undoped control under the same bias current has been observed. According to the measured electrical-to-optical bandwidths and extracted RC-limited bandwidths of both devices, the superior Speed performance can be attributed to higher electron/hole radiative recombination rate in the n-doped MQW than that of undoped MQW
-
Modulation Speed enhancement of a gan based green light emitting diode led by use of n type barrier doping for plastic optical fiber pof communication
Quantum Electronics and Laser Science Conference, 2006Co-Authors: H Y Huang, Jin-wei Shi, J I Chyi, Y S Wu, Jinnkong Sheu, W C Lai, Gongru Lin, Ciling PanAbstract:We demonstrate a high-Speed green GaN light-emitting-diode for plastic optical fiber communication. By use of n-type doping in barrier layers, superior performance of Modulation-Speed and output-power to undoped control has been observed.