Passively generated Q-switched pulses fiber laser in 2 μm wavelength using MXene Ti₃C₂T_x and Ti₂CT_x saturable absorber

Abstract In this paper, Q-switched Thulium-doped fiber lasers (TDFLs) operating near the 2 μm region were demonstrated, utilizing a newly developed Thulium doped fiber as the gain medium and titanium carbide MXene as the saturable absorber (SA). The Thulium-doped fiber with a composition of SiO 2 -GeO 2 -Al 2 O 3 -HfO 2 -Y 2 O 3 -Bi 2 O 3, was produced from a preform prepared using the modified chemical vapor deposition (MCVD) process. Two variations of titanium carbide MXene-based SA, Ti 3 C 2 T x and Ti 2 CT x , were tested and compared, successfully generating Q-switched pulses. When Ti 3 C 2 T x was used, the Q-switched pulse had a center wavelength of 1934.223 nm, a repetition rate of 55.39 kHz and a pulse width and 1.942 μs. For Ti 2 CT x , the generated Q-switched pulse has a center wavelength of 1932.229 nm, with a repetition rate of 77.28 kHz and a pulse width of 1.608 μs. The signal-to-noise ratio (SNR) values were 45.6 dB and 50.2 dB for Ti 3 C 2 T x and Ti 2 CT x respectively. Based on the experimental results, both Ti 3 C 2 T x and Ti 2 CT x show promise as SAs for generating Q-switched pulses in the 2 μm region within the TDFL cavity.