Evolution of Complex Pulse-Bunches in a Bound-State Soliton Fiber Laser

The evolution of complex pulse-bunches in a bound-state soliton fiber laser with a MoS2 saturable absorber is observed with increasing pump laser power. The experiment demonstrated that the stable two-soliton bound state with fixed and tight separation was achieved, inducing strong interplay between the two solitons. The fundamental bound-state mode-locking operations were maintained and the pulse train gradually evolved into complex pulse-bunches to balance the accumulated cavity nonlinear effects as the pump power increased. Our results may offer a platform for the commercial development of stable double-pulse laser sources.