In this paper, antimony trisulfide (Sb2S3) was successfully prepared with the liquid phase exfoliation method and embedded into polyvinyl alcohol (PVA) as a saturable absorber (SA) in a passively mode-locked Er-doped fiber laser for the first time. Based on Sb2S3-PVA SA with a modulation depth of 4.0% and a saturable intensity of 1.545 GW/cm2, a maximum average output power of 3.04 mW and maximum peak power of 325.6 W for the stable mode-locked pulses was achieved with slope a efficiency of 0.87% and maximum single pulse energy of 0.81 nJ at a repetition rate of 3.47 MHz under a pump power of 369 mW. A minimum pulse width value of 2.4 ps with a variation range less than 0.1 ps, and a maximum signal to noise ratio (SNR) of 54.3 dB indicated reliable stability of mode-locking, revealing promising potentials of Sb2S3 as a saturable absorber in ultrafast all-fiber lasers.
Keywords: antimony trisulfide; fiber laser; mode-locked; saturable absorber.