Browsing by Author "Lu, Yun-Ting"

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850/940-nm VCSEL for optical communication and 3D sensing
(2018-01-01)
Cheng, Chih-Hsien
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Shen, Chih-Chiang
;
Kao, Hsuan-Yun
;
Hsieh, Dan-Hua
;
Wang, Huai-Yung
This paper is going to review the state-of-the-art of the high-speed 850/940-nm vertical cavity surface emitting laser (VCSEL), discussing the structural design, mode control and the related data transmission performance. InGaAs/AlGaAs multiple quantum well (MQW) was used to increase the differential gain and photon density in VCSEL. The multiple oxide layers and oxide-confined aperture were well designed in VCSEL to decrease the parasitic capacitance and generate single mode (SM) VCSEL. The maximal modulation bandwidth of 30 GHz was achieved with well-designed VCSEL structure. At the end of the paper, other applications of the near-infrared VCSELs are discussed.
Design and Fabrication of the Reliable GaN Based Vertical-Cavity Surface-Emitting Laser via Tunnel Junction
(2019-04-01)
Shen, Chih-Chiang
;
Lu, Yun-Ting
;
Yeh, Yen-Wei
;
Chen, Cheng-Yuan
;
Chen, Yu-Tzu
In this study, we theoretically designed and experimentally fabricated an InGaN vertical-cavity surface-emitting laser (VCSEL) with a tunnel junction (TJ) structure. From numerical simulation results, the optical loss of the device can be reduced by a TJ structure. Additionally, the leakage current of the VCSEL with TJ structure was much smaller than that of the VCSEL with an Indium-Tin-Oxide (ITO) layer. We have been demonstrated that laser output performance is improved by using the TJ structure when compared to the typical VCSEL structure of the ITO layer. The output power obtained at 2.1 mW was enhanced by a factor of 3.5 by the successful reduction of threshold current density (J(th)) from 12 to 8.5 kA/cm(2), and the enlarged slope efficiency was due to less absorption in VCSEL with a TJ structure. Finally, the samples passed the high temperature (70 degrees C) and high operation current (1.5 x J(th)) test for over 500 h.
Design, Modeling, and Fabrication of High-Speed VCSEL with Data Rate up to 50 Gb/s
(2019-08-14)
Shen, Chih-Chiang
;
Hsu, Tsung-Chi
;
Yeh, Yen-Wei
;
Kang, Chieh-Yu
;
Lu, Yun-Ting
We have studied the characteristics of frequency response at 850-nm GaAs high-speed vertical-cavity surface-emitting lasers (VCSELs) with different kinds of oxide aperture sizes and cavity length using the PICS3D simulation program. Using 5-mu m oxide aperture sizes, the frequency response behavior can be improved from 18.4 GHz and 15.5 GHz to 21.2 GHz and 19 GHz in a maximum of 3 dB at 25 degrees C and 85 degrees C, respectively. Numerical simulation results also suggest that the frequency response performances improved from 21.2 GHz and 19 GHz to 30.5 GHz and 24.5 GHz in a maximum of 3 dB at 25 degrees C and 85 degrees C due to the reduction of cavity length from 3 lambda/2 to lambda/2. Consequently, the high-speed VCSEL devices were fabricated on a modified structure and exhibited 50-Gb/s data rate at 85 degrees C.
Simulation Model of Oxide-Aperture Strain Quantum Well VCSEL
(2019-01-01)
Shih, Hsiang-Yun
;
Cho, Yu-Yun
;
Hsu, Shun-Chieh
;
Huang, Yu-Ming
;
Wang, Shou-Wei
An oxide aperture strained quantum well VCSEL model was built based on measured results. The indium composition of MQW was changed to maximize the frequency response. The simulation result shows that the bandwidth can be improved and reach 30.88GHz.