MXene Ti₃C₂T_x thin film as a saturable absorber for passively mode-locked and Q-switched fibre laser

We have experimentally demonstrated the mode-locked and Q-switched fibre lasers based on MXene Ti₃C₂T _x as a saturable absorber (SA). MXene Ti₃C₂T _x was obtained using selective etching and then embedded into polyvinyl alcohol (PVA) to form the thin film. A stable soliton mode-locked laser was achieved when the Ti₃C₂T _x film was added in the Erbium-doped fibre laser cavity, and the pump power was adjusted between 55 and 144 mW. The pulse width of mode-locked laser was obtained to be 3.68 ps, while the repetition rate was 1.89 MHz. The maximum average output power and pulse energy were measured to be 24.42 mW and 12.92 nJ. After we decreased the cavity length by removing 100 m of SMF, the same SA could produce Q-switched laser instead of mode-locked laser. The Q-switched laser operated within the pump power of 19–66 mW, having the shortest pulse width and operating wavelength of 2.6 µs and 1557 nm, respectively.