Tunable mode-locked thulium doped fiber laser using manganese phosphorus triselenide (MnPSe3) in 2.0 μm

Abstract

This work demonstrates a passive technique to generate mode-locked pulses in a thulium-doped fiber laser (TDFL) using manganese phosphorus triselenide (MnPSe3) as the saturable absorber (SA). The MnPSe3 solution was prepared through the liquid phase exfoliation technique (LPE) and was then deposited onto an arc-shaped fiber through the drop-casting method. A highly stable mode-locked laser with a center wavelength of 1937.0 nm and a 2.69 nm bandwidth was generated when the MnPSe3 SA was inserted into the fiber laser ring cavity. The fundamental frequency of the mode-locked TDFL was 13.10 MHz and the signal-to-noise ratio (SNR) was 49 dB. The mode-locked pulse had a pulse duration of 1.56 ps. By stretching the arc-shaped fiber using a mechanical stage, the center wavelength of the laser could be tuned from 1937 to 1939 nm. The successful generation of the mode-locking operation indicates that MnPSe3-SA is suitable to operate in the 2.0 μm wavelength region.