Mode-locked thulium-doped fiber laser with WSe2 based evanescent field interaction

We report, for the first time to our knowledge, the usage of CVD-grown few-layer WSe₂ as a saturable absorber for the mode locking of a thulium-doped fiber laser. The WSe₂ saturable absorber was deposited on the waist of the tapered fiber. By employing the WSe₂ saturable absorber, we demonstrate a passively mode-locked fiber laser operating at 1863.96 nm with a 3 dB spectral bandwidth of 2.89 nm. The fundamental repetition rate was 11.357 MHz with a signal-to-noise ratio of 85 dB.