Generation of dark solitons in a self-mode-locked Tm-Ho doped fiber laser

Abstract

We present the first experimental demonstration of self-mode-locked dark solitons in a Tm-Ho doped fiber laser at 1.93 μm with an average power of 149.6 mW and repetition rate of 15.9 MHz. In our system, the dark solitons are generated by self-mode-locking via exploiting the reverse saturable excited-state absorption of a gain fiber, which achieves a higher damage threshold and accordingly laser power over conventional methods based on extra saturable absorber or nonlinear polarization rotation. In the experiments, we study the evolution from high-order to low-order dark solitons by adjusting the pump power, which is attributed to the excited-state absorption in Tm3+ between 3F4 and 3H4 energy level. Simulations have been performed to show dark soliton generation by the reverse-saturable absorption mechanism in Tm-Ho doped fiber laser based on the extended nonlinear Schrödinger equation. The results confirm our new approach can generate stable dark solitons of high average power, which may find important applications in laser sensing and laser communications.