Few-layer MoS2 grown by chemical vapor deposition as a passive Q-switcher for tunable erbium-doped fiber lasers

We report an erbium-doped fiber laser passively Q-switched by a few-layer molybdenum disulfide (MoS2) saturable absorber (SA). The few-layer MoS2 is grown by the chemical vapor deposition method and transferred onto the end-face of a fiber connector to form a fiber-compatible MoS2 SA. The laser cavity is constructed by using a three-port optical circulator and a fiber Bragg grating (FBG) as the two end-mirrors. Stable Q-switched pulses are obtained with a pulse duration of 1.92 mu s at 1560.5 nm. By increasing the pump power from 42 to 204 mW, the pulse repetition rate can be widely changed from 28.6 to 114.8 kHz. Passive Q-switching operations with discrete lasing wavelengths ranging from 1529.8 to 1570.1 nm are also investigated by using FBGs with different central wavelengths. This work demonstrates that few-layer MoS2 can serve as a promising SA for wideband-tunable Q-switching laser operation. (C) 2015 Chinese Laser Press