Passively mode-locking fiber laser based on Cr2Si2Te6 saturable absorber

This paper reports on the generation of third-order harmonic mode-locking, double-pulse phenomena, and conventional solitons in an erbium-doped fiber laser using Cr₂Si₂Te₆ as a saturable absorber (SA). The double-balance probing method was employed to examine the nonlinear characteristics of Cr₂Si₂Te₆-SA. Its modulation depth is 2.35 %, and its saturation intensity is 29.74 MW/cm². We discovered conventional soliton functioning with a center wavelength of 1561.8 nm at a pump power of 34.76 mW. It has a repetition frequency of 6.76 MHz and a signal-to-noise ratio of 45 dB. As the pump power increased, the traditional soliton was able to maintain its existence in the range of 34.76 mW to 80.96 mW. The maximum output power reaches 1.1 mW when the pump power is 80.96 mW, and the maximum single-pulse energy of the conventional soliton is 0.16 nJ. Furthermore, we observed third-order harmonic mode-locking and double-pulse phenomena at pump outputs of 53.65 mW and 71.16 mW. The experimental findings demonstrate the excellent nonlinear effect of the SA based on Cr₂Si₂Te₆. In ultrashort-pulse fiber lasers, Cr₂Si₂Te₆ nanosheets can be employed as an efficient saturable absorption material.