Mechanism of solitary wave breaking phenomenon in dissipative soliton fiber lasers.

We numerically and experimentally investigate the pulse evolution to the edge of destabilization against pumping powers in a strongly dissipative-dispersive laser configuration mode locked by nonlinear polarization evolution (NPE) technique. Two distinct dynamic processes are indicated by numerical results and further evidenced by experimental observations, where one depicts the monotonous increase in peak power and slight narrowing of duration, the other is different in exhibiting obvious broadening in temporal domain. Correspondingly, it is demonstrated in the simulation of cavity dynamics that the artificial saturable absorber plays two opposite roles in pulse shaping, which implies the switch of cavity feedback. Mechanisms with respect to different cavity feedbacks are analyzed based on a newly-proposed theoretical viewpoint, for positive feedback single pulse operation is restricted by the limit of peak power mainly dependent of the gain bandwidth; for negative feedback the breakup is attributed to the limited strength of clamping effect determined by multiple ingredients.