Passively harmonic mode-locked erbium-doped fiber laser based on 2H-MoTe2 saturable absorber

Abstract We demonstrated a harmonic mode-locked Erbium-doped fiber laser based on a saturable absorber (SA) of 2H-MoTe 2 , which is a member of the transition metal dichalcogenides. The SA mode-locker was made by integrating the 2H-MoTe 2 into a D-shaped fiber, and then was inserted into an erbium-doped fiber laser for mode-locking. The nonlinear modulation depth and saturation power of 2H-MoTe 2 -based SA were 10.9% and 19 MW cm −2 , respectively. The fundamentally mode-locked pulse train had a pulse width of 577 fs and a repetition rate of 14.32 MHz. The highest order of harmonic mode locking was 55th, which had the repetition rate of 787.6 MHz, pulse width of 820 fs and average output power of 11.8 mW. To the best of our knowledge, this is the highest operating repetition frequency that has ever been demonstrated in a 2H-MoTe 2 -based fiber laser. The experimental results validate the feasibility of 2H-MoTe 2 as a promising SA for generating ultrashort pulses with high repetition rates.