The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Hongda Chen - One of the best experts on this subject based on the ideXlab platform.
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Polarization stable low threshold current single Fundamental Mode VCSELs
Optical Materials Express, 2015Co-Authors: Yiyang Xie, Qiang Kan, Meng Xun, Hongda ChenAbstract:The characteristics of polarization stable microstructure vertical-cavity surface-emitting lasers (PS-MS-VCSELs) with low threshold current and single Fundamental Mode (SFM) operation were theoretically and experimentally investigated. Elliptical air hole photonic crystal (EPC) structure was incorporated in the top mirror of the MS-VCSELs to realize single Fundamental Mode operation. By controlling the Mode loss difference among the two orthogonal Modes, the Fundamental Mode and other high order Modes of the MS-VCSELs, through suitable oxide aperture shape and EPC parameters, a high performance PS-MS-VCSEL is achieved with output power of 1.6 mW, low threshold current of 0.8 mA as well as more than 20 dB orthogonal polarization suppression ratio (OPSR).
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multi point defect single Fundamental Mode photonic crystal vertical cavity surface emitting laser
Optics and Laser Technology, 2013Co-Authors: Yiyang Xie, Qiang Kan, Chun-xia Wang, Hongda ChenAbstract:Abstract A seven-point-defect photonic crystal (PhC) vertical cavity surface emitting laser (VCSEL) operating with high single-Fundamental-Mode of 2.3 mW and low threshold current of 1.2 mA was demonstrated and its performance was analyzed. The single-Fundamental-Mode emission aperture (central defect area) was enlarged to achieve high output power. Furthermore, suitable refractive index step due to the photonic crystal structure was obtained to overcome the external index perturbations, which can be attributed to stable single-Fundamental-Mode operation even at saturation current. The transverse Mode confinement characteristics by photonic crystal was analyzed based on the effective index Model and showed good agreement with the experiment results.
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Low Threshold Current Single-Fundamental-Mode Photonic Crystal VCSELs
IEEE Photonics Technology Letters, 2012Co-Authors: Yiyang Xie, Qiang Kan, Zhu Yanxu, Chun-xia Wang, Hongda ChenAbstract:An optimization of oxide aperture diameter to match the light emission aperture (the central defect region) in the photonic crystal vertical-cavity surface-emitting laser (PhC-VCSEL) is presented in order to obtain low threshold current and high single-Fundamental-Mode output of the device. A 3-D finite-difference time-domain method has been applied to simulate the Mode field distribution and quality factors (Q factors) of Fundamental and high order transverse Modes which correspond to the Mode loss of the PhC-VCSEL cavity. Single-Fundamental-Mode operation of PhC-VCSEL with 1.7-mW output power and low threshold current of 0.7-mA is demonstrated after oxide aperture optimization.
Yiyang Xie - One of the best experts on this subject based on the ideXlab platform.
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Polarization Bistable Single Fundamental Mode Photonic Crystal VCSELs
Conference on Lasers and Electro-Optics, 2020Co-Authors: Qiuhua Wang, Yiyang Xie, Guanzhong Pan, Yibo DongAbstract:The polarization bistable (PB) single Fundamental Mode VCSEL was realized by using dual Mode confinement microstructure, rhombus shape-oxide aperture and photonic crystal. As the injection current increasing, the device polarization direction has been changed.
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Polarization stable low threshold current single Fundamental Mode VCSELs
Optical Materials Express, 2015Co-Authors: Yiyang Xie, Qiang Kan, Meng Xun, Hongda ChenAbstract:The characteristics of polarization stable microstructure vertical-cavity surface-emitting lasers (PS-MS-VCSELs) with low threshold current and single Fundamental Mode (SFM) operation were theoretically and experimentally investigated. Elliptical air hole photonic crystal (EPC) structure was incorporated in the top mirror of the MS-VCSELs to realize single Fundamental Mode operation. By controlling the Mode loss difference among the two orthogonal Modes, the Fundamental Mode and other high order Modes of the MS-VCSELs, through suitable oxide aperture shape and EPC parameters, a high performance PS-MS-VCSEL is achieved with output power of 1.6 mW, low threshold current of 0.8 mA as well as more than 20 dB orthogonal polarization suppression ratio (OPSR).
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multi point defect single Fundamental Mode photonic crystal vertical cavity surface emitting laser
Optics and Laser Technology, 2013Co-Authors: Yiyang Xie, Qiang Kan, Chun-xia Wang, Hongda ChenAbstract:Abstract A seven-point-defect photonic crystal (PhC) vertical cavity surface emitting laser (VCSEL) operating with high single-Fundamental-Mode of 2.3 mW and low threshold current of 1.2 mA was demonstrated and its performance was analyzed. The single-Fundamental-Mode emission aperture (central defect area) was enlarged to achieve high output power. Furthermore, suitable refractive index step due to the photonic crystal structure was obtained to overcome the external index perturbations, which can be attributed to stable single-Fundamental-Mode operation even at saturation current. The transverse Mode confinement characteristics by photonic crystal was analyzed based on the effective index Model and showed good agreement with the experiment results.
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Low Threshold Current Single-Fundamental-Mode Photonic Crystal VCSELs
IEEE Photonics Technology Letters, 2012Co-Authors: Yiyang Xie, Qiang Kan, Zhu Yanxu, Chun-xia Wang, Hongda ChenAbstract:An optimization of oxide aperture diameter to match the light emission aperture (the central defect region) in the photonic crystal vertical-cavity surface-emitting laser (PhC-VCSEL) is presented in order to obtain low threshold current and high single-Fundamental-Mode output of the device. A 3-D finite-difference time-domain method has been applied to simulate the Mode field distribution and quality factors (Q factors) of Fundamental and high order transverse Modes which correspond to the Mode loss of the PhC-VCSEL cavity. Single-Fundamental-Mode operation of PhC-VCSEL with 1.7-mW output power and low threshold current of 0.7-mA is demonstrated after oxide aperture optimization.
Qiang Kan - One of the best experts on this subject based on the ideXlab platform.
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Polarization stable low threshold current single Fundamental Mode VCSELs
Optical Materials Express, 2015Co-Authors: Yiyang Xie, Qiang Kan, Meng Xun, Hongda ChenAbstract:The characteristics of polarization stable microstructure vertical-cavity surface-emitting lasers (PS-MS-VCSELs) with low threshold current and single Fundamental Mode (SFM) operation were theoretically and experimentally investigated. Elliptical air hole photonic crystal (EPC) structure was incorporated in the top mirror of the MS-VCSELs to realize single Fundamental Mode operation. By controlling the Mode loss difference among the two orthogonal Modes, the Fundamental Mode and other high order Modes of the MS-VCSELs, through suitable oxide aperture shape and EPC parameters, a high performance PS-MS-VCSEL is achieved with output power of 1.6 mW, low threshold current of 0.8 mA as well as more than 20 dB orthogonal polarization suppression ratio (OPSR).
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multi point defect single Fundamental Mode photonic crystal vertical cavity surface emitting laser
Optics and Laser Technology, 2013Co-Authors: Yiyang Xie, Qiang Kan, Chun-xia Wang, Hongda ChenAbstract:Abstract A seven-point-defect photonic crystal (PhC) vertical cavity surface emitting laser (VCSEL) operating with high single-Fundamental-Mode of 2.3 mW and low threshold current of 1.2 mA was demonstrated and its performance was analyzed. The single-Fundamental-Mode emission aperture (central defect area) was enlarged to achieve high output power. Furthermore, suitable refractive index step due to the photonic crystal structure was obtained to overcome the external index perturbations, which can be attributed to stable single-Fundamental-Mode operation even at saturation current. The transverse Mode confinement characteristics by photonic crystal was analyzed based on the effective index Model and showed good agreement with the experiment results.
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Low Threshold Current Single-Fundamental-Mode Photonic Crystal VCSELs
IEEE Photonics Technology Letters, 2012Co-Authors: Yiyang Xie, Qiang Kan, Zhu Yanxu, Chun-xia Wang, Hongda ChenAbstract:An optimization of oxide aperture diameter to match the light emission aperture (the central defect region) in the photonic crystal vertical-cavity surface-emitting laser (PhC-VCSEL) is presented in order to obtain low threshold current and high single-Fundamental-Mode output of the device. A 3-D finite-difference time-domain method has been applied to simulate the Mode field distribution and quality factors (Q factors) of Fundamental and high order transverse Modes which correspond to the Mode loss of the PhC-VCSEL cavity. Single-Fundamental-Mode operation of PhC-VCSEL with 1.7-mW output power and low threshold current of 0.7-mA is demonstrated after oxide aperture optimization.
Chun-xia Wang - One of the best experts on this subject based on the ideXlab platform.
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multi point defect single Fundamental Mode photonic crystal vertical cavity surface emitting laser
Optics and Laser Technology, 2013Co-Authors: Yiyang Xie, Qiang Kan, Chun-xia Wang, Hongda ChenAbstract:Abstract A seven-point-defect photonic crystal (PhC) vertical cavity surface emitting laser (VCSEL) operating with high single-Fundamental-Mode of 2.3 mW and low threshold current of 1.2 mA was demonstrated and its performance was analyzed. The single-Fundamental-Mode emission aperture (central defect area) was enlarged to achieve high output power. Furthermore, suitable refractive index step due to the photonic crystal structure was obtained to overcome the external index perturbations, which can be attributed to stable single-Fundamental-Mode operation even at saturation current. The transverse Mode confinement characteristics by photonic crystal was analyzed based on the effective index Model and showed good agreement with the experiment results.
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Low Threshold Current Single-Fundamental-Mode Photonic Crystal VCSELs
IEEE Photonics Technology Letters, 2012Co-Authors: Yiyang Xie, Qiang Kan, Zhu Yanxu, Chun-xia Wang, Hongda ChenAbstract:An optimization of oxide aperture diameter to match the light emission aperture (the central defect region) in the photonic crystal vertical-cavity surface-emitting laser (PhC-VCSEL) is presented in order to obtain low threshold current and high single-Fundamental-Mode output of the device. A 3-D finite-difference time-domain method has been applied to simulate the Mode field distribution and quality factors (Q factors) of Fundamental and high order transverse Modes which correspond to the Mode loss of the PhC-VCSEL cavity. Single-Fundamental-Mode operation of PhC-VCSEL with 1.7-mW output power and low threshold current of 0.7-mA is demonstrated after oxide aperture optimization.
Jung-min Yang - One of the best experts on this subject based on the ideXlab platform.
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Fault tolerant control of asynchronous sequential machines with transient faults in non-Fundamental Mode
Automatica, 2020Co-Authors: Jung-min YangAbstract:Abstract This paper addresses fault tolerant corrective control of asynchronous sequential machines (ASMs) against transient faults causing unauthorized state transitions. While the prior work considers only those kinds of faults that comply with Fundamental Mode operations, the constraint is relaxed in this study. Hence the transient faults may occur not only in Fundamental Mode, or when the machine stays at a stable state, but also in non-Fundamental Mode, or when the machine passes through transient states. The condition for overcoming transient faults occurring in non-Fundamental Mode turns out to be stricter than the case of Fundamental Mode. A novel scheme of corrective control is presented to make the closed-loop system immune against any fault occurrence in non-Fundamental Mode. An illustrative example is provided to demonstrate the synthesis procedure of the proposed corrective controller.
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Burst-feedback corrective control of asynchronous sequential machines in non-Fundamental Mode
Journal of the Franklin Institute, 2020Co-Authors: Jung-min YangAbstract:Abstract Corrective control can compensate for the stable-state behavior of asynchronous sequential machines (ASMs) in a desirable way. This paper presents fault tolerant corrective control for a class of ASMs where output burst, a quick succession of output characters produced along asynchronous transitions, is given as output feedback. The considered ASM is vulnerable to transient faults that may occur during transient transitions of the machine, or in non-Fundamental Mode. Compared with the prior work on those faults occurring in Fundamental Mode, the control objective and the reachability conditions for fault recovery are more restrictive in the case of non-Fundamental Mode. Based on corrective control theory, we address a scheme of fault diagnosis and fault tolerant control for the closed-loop system to overcome every transient fault causing unauthorized state transitions. An illustrative example is provided to validate the synthesis procedure of the proposed burst-feedback corrective control scheme.
