Passively mode-locked erbium-doped fiber laser by a Mo₂TiC₂ MXene saturable absorber

Mono- and few-layer MXenes have gained widespread use as a nonlinear material platform for saturable absorbers (SAs) when generating ultrafast mode-locked pulses. However, the manufacturing processes associated with these materials are intricate and require considerable expertise. Consequently, it would be intriguing to investigate whether bulk and/or nanoscale-layered MXenes can be used as a nonlinear optical material platform. In this study, we experimentally demonstrated a Mo₂TiC₂ MXene-based SA by depositing nanoscale-layered Mo₂TiC₂ MXene particles and a polyvinyl alcohol composite film onto a side-polished fiber device. The fabricated SA exhibited a modulation depth of 5.67% and a saturation intensity of 0.135 MW/cm². By integrating the Mo₂TiC₂ MXene-based SA within an erbium-doped fiber ring cavity, we generated mode-locked pulses featuring a pulse width of 1.74 ps at a wavelength of 1557.9 nm. This investigation highlights the potential of nanoscale-layered Mo₂TiC₂ MXene to function as an efficient material platform for nonlinear photonics applications.