Passive harmonic mode-locking of Er-doped fiber laser using CVD-grown few-layer MoS2 as a saturable absorber**Project supported by the National Natural Science Foundation of China (Grant Nos. 61378028, 61421002, 61475030, and 61377042), the National Basic Research Program of China (Grant No. 2012CB315701), and the New Century Excellent Talents Program in University, China (Grant No. NCET-13-0092).

Abstract

Passive harmonic mode locking of an erbium-doped fiber laser based on few-layer molybdenum disulfide (MoS2) saturable absorber (SA) is demonstrated. The few-layer MoS2 is prepared by the chemical vapor deposition (CVD) method and then transferred onto the end face of a fiber connector to form a fiber-compatible MoS2 SA. The 20th harmonic mode-locked pulses at 216-MHz repetition rate are stably generated with a pulse duration of 1.42 ps and side-mode suppression ratio (SMSR) of 36.1 dB. The results confirm that few-layer MoS2 can serve as an effective SA for mode-locked fiber lasers.