Self-Healing of Pulse Drop-Outs in Harmonically Mode-Locked Soliton Fiber Laser Through Satellite Pulse Generation

Pulse drop-out is a generic issue in harmonically mode-locked (HML) lasers [1] which leads to irregular output pulse train with undesired empty slots. Although previous studies have suggested means to mitigate it by stabilizing pulse amplitude fluctuations [2], simple recovery method from accidental drop-outs are demanded to ensure a robust long-term operation of the HML laser [3]. In this work, we report a unique self-healing effect through satellite pulse generations observed in HML soliton fiber laser. The HML laser is based on the established mechanism of optoacoustic mode-locking using photonic crystal fiber (PCF) [4]. The drop-outs within the soliton sequence can be refilled by randomly-generated satellite pulses through pump-power perturbation, which quickly evolved into laser solitons in these empty slots. Meanwhile, the pre-existing solitons in the sequence remain in their positions after inevitable collisions with these satellite pulses, thanks to their intrinsic stability (Fig. 1(a)). The results suggest an feasible route for global manipulation of solitons in HML laser by exploring the parameter space of the laser cavity for tailorable self-stabilization properties of laser solitons.