Passively mode-locked thulium-holmium co-doped fiber laser using hybrid side polished fiber with MoWS2-rGO nanocomposite

Passive mode-locking pulse generation in a Thulium-Holmium doped fiber laser (THDFL) with molybdenum tungsten disulfide-reduced graphene oxide (MoWS2-rGO) nanocomposite saturable absorber (SA) was demonstrated for operation in 2.0 mu m wavelength regions. Mode-locked pulse was achieved by the evanescent wave interaction with the MoWS2-rGO based SA embedded on a side polished fiber. The THDFL produces mode-locked pulses centered at 1908.6 nm with a repetition rate and pulse duration of 11.9 MHz and 1.5 ps, respectively. A high signal to noise ratio (SNR) of 48 dB as well as minimal power and wavelength fluctuations indicates the excellent stability of the mode-locking operation. To the best of our knowledge, it is the first demonstration of MoWS2-rGO used as a SA in the THDFL system. The proposed laser would benefit various domains, mainly medicine, for its operation in the eye-safe 2.0 mu m wavelength region.