All-fiberized, femtosecond laser at 1912 nm using a bulk-like MoSe₂ saturable absorber

An all-fiberized, mode-locked fiber laser that operates in the 1912 nm region with a saturable absorber (SA) that is based on a composite consisting of bulk-like, molybdenum diselenide (MoSe₂) particles and polyvinyl alcohol (PVA), is experimentally demonstrated here. The MoSe₂ particles were prepared using liquid phase exfoliation (LPE) without a centrifugation. The SA was implemented on a side-polished fiber platform and deposited with the MoSe₂/PVA. The saturation power and modulation depth of the SA were measured as ~25.7 W and ~4.4%, respectively. Using the prepared SA, the stable soliton pulses with a temporal width of ~920 fs could be produced at 1912 nm from a thulium-holmium (Tm-Ho) co-doped fiber ring cavity. The mode-locked pulses were operated at a repetition rate of ~18.21 MHz, and a 3-dB bandwidth was measured as ~4.62 nm. The signal-to-noise ratio (SNR) was measured as ~65 dB at the fundamental frequency of ~18.21 MHz. To the best of the authors' knowledge this is the first time demonstration of the use of a saturable absorber based on a transition metal dichalcogenide for femtosecond mode-locking of a 2-μm fiber laser.