Harmonic and fundamental-frequency mode-locked operations in an Er-doped fiber laser using a Cr2Si2Te6-based saturable absorber

Abstract

In our work, Cr2Si2Te6, a novel two-dimensional (2D)-layered ferromagnetic insulator, was used as a saturable absorber (SA) for demonstrating a pulsed Er-doped fiber laser (EDFL) based on its nonlinear saturable absorption properties. The modulation depth and saturation intensity of the Cr2Si2Te6-based SA are 6.61% and 10.77 MW/cm2, respectively. When the pump power is 60.3 mW, the 13th harmonic mode-locked generation is obtained, the 3 dB optical spectrum bandwidth is 1.392 nm and the central wavelength is 1568.032 nm. When the pump power is higher than 170.3 mW, the EDFL works at the fundamental repetition frequency of 1.23 MHz with a signal-to-noise ratio of 25 dB. The experimental results reveal that Cr2Si2Te6 SA has enormous potential in demonstrating ultrafast fiber lasers and provide references for future research based on Cr2Si2Te6 as ultrafast optical modulators.