171st-order harmonic soliton erbium-doped fiber laser based on 2H-MoTe2 saturable absorber

We have demonstrated a high order harmonic mode-locked erbium-doped fiber laser by utilizing 2H-MoTe2 film as a saturable absorber (SA). The SA is synthesized by depositing 2H-MoTe2 film on a D-shaped fiber. The nonlinear optical properties of the 2H-MoTe2 SA are characterized, showing a modulation depth of 14.7% and a saturation intensity of 3 GW cm−2. Through optimizing the pump power and intra-cavity polarization state, a 171st-order harmonic soliton at 0.9 GHz repetition frequency with a pulse width of 1.06 ps was obtained. The fundamentally mode-locked pulse train had a pulse width of 1.03 ps and a repetition rate of 5.33 MHz. To the best of our knowledge, the 171st-order harmonic soliton is the highest operating repetition frequency that has ever been demonstrated in a 2H-MoTe2 SA mode locked fiber laser. The results indicate the potential of 2H-MoTe2 SA at high repetition rates regimes, which could benefit for future possible application.