Ternary 2D Mo(1-x)WxS2 as a saturable absorber for femtosecond mode-locked all fiber lasers

Abstract In this paper, we utilized the ternary Mo(1-x)WxS2 alloys to fabricate Mo0.5W0.5S2 film, which serve as a ultrashort pulse mode-locker in erbium-doped all fiber lasers (EDFL). The modulation depth, saturable intensity and unsaturated loss of the film SA were 12%, 4.5 MW/cm2 and 67.1% respectively. Stable self-mode-locking pulses could be achieved with a threshold pump power of 60 mW. With the increasing pump power, the pulse was centered at 1556.8 nm ~ 1558.1 nm with pulse width of 575 fs ~ 800 fs. The shortest pulse width, fundamental repetition rate and maximum pulse energy is 575 fs, 4.873 MHz, and 0.154 nJ, respectively. The signal to noise ratio (SNR) was measured to be about 53 dB. For the first time, we have experimentally demonstrated a mode-locked EDFL based on Mo0.5W0.5S2 SA. To the best of our knowledge, this was the first realization of femtosecond photonics based on Mo0.5W0.5S2 SAs. Our results suggest that Mo0.5W0.5S2 SA is a promising candidate for mode-locked ultrafast fiber laser in optoelectronic and optical communications applications.