Soliton mode-locked erbium-doped fibre laser with mechanically exfoliated molybdenum disulphide saturable absorber

The authors demonstrate the generation of soliton mode-locked pulses from an erbium-doped fibre ring laser incorporating molybdenum disulphide (MoS2) saturable absorber (SA) with a net anomalous dispersion. The MoS2 SA is prepared by mechanically exfoliating MoS2 crystal and fixing the acquired MoS2 flakes onto the end surface of a standard FC/PC fibre connector. A self-started mode-locked soliton pulse is generated by fine-tuning the rotation of the polarisation controller at the threshold pump power of 50 mW. Its solitonic behaviour is verified by the presence of Kelly sidebands in the output spectrum. The central wavelength, 3 dB bandwidth, pulsewidth, and repetition rate of the laser are 1598.94 nm, 5.4 nm, 0.83 ps, and 17.1 MHz, respectively. The maximum pulse energy is 74 nJ at pump power of 110 mW with the output power of 1.26 mW. The MoS2 SA was constructed in a simple fabrication process and has a modulation depth of 11.3% to successfully produce the stable soliton mode-locked fibre laser.