Investigation of regime switching from mode locking to Q-switching in a 2 µm InGaSb/AlGaAsSb quantum well laser

• Main Authors: Li, Xiang, Wang, Hong, Qiao, Zhongliang, Guo, Xin, Wang, Wanjun, Ng, Geok Ing, Zhang, Yu, Xu, Yingqiang, Niu, Zhichuan, Tong, Cunzhu, Liu, Chongyang
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2018
• Subjects: Diode Lasers; Mode-locked Laser
• Online Access: https://hdl.handle.net/10356/88342; http://hdl.handle.net/10220/44607
• Institution: Nanyang Technological University

A two-section InGaSb/AlGaAsSb single quantum well (SQW) laser emitting at 2 μm is presented. By varying the absorber bias voltage with a fixed gain current at 130 mA, passive mode locking at ~18.40 GHz, Q-switched mode locking, and passive Q-switching are observed in this laser. In the Q-switched mode locking regimes, the Q-switched RF signal and mode locked RF signal coexist, and the Q-switched lasing and mode-locked lasing happen at different wavelengths. This is the first observation of these three pulsed working regimes in a GaSb-based diode laser. An analysis of the regime switching mechanism is given based on the interplay between the gain saturation and the saturable absorption.