Passive Q-switched fiber laser with MAX phase molybdenum titanium aluminum carbide film

In this work, we demonstrate a Q-switched erbium-doped fiber laser (EDFL), which is passively produced by using a saturable absorber (SA), which is fabricated by mechanical exfoliation of MAX phase molybdenum titanium aluminum carbide (Mo2Ti2AlC3). Physical and optical properties of the SA are experimentally studied. The optical properties showed a good nonlinear absorption where the saturation intensity is 0.65 MW/cm2, with 40% of non-saturable absorption and 17% of modulation depth. The proposed EDFL is investigated using two output couplers (OCs) with split ratios of 50:50 and 80:20, respectively. For pumping power of 142 mW and coupling ratio of 50%, the proposed EDFL produced pulses with a pulse energy of 69.60 nJ, pulse width of 2.97 μs and repetition rate of 90.09 kHz. Besides, with coupling ratio of 20%, the EDFL can generate a pulse train with a pulse width of 1.91 μs, repetition rate of 77.64 kHz, and pulse energy of 89.52 nJ.