Dynamics of soliton explosions in passively mode-locked fiber lasers

Abstract

A soliton explosion is an instability whereby a dissipative soliton undergoes a sudden structural collapse but remarkably returns back to its original shape after a short transient. We recently reported the first experimental observation of this effect in a fiber laser [Optica2, 36 (2015)10.1364/OPTICA.2.000036]. Here, we expand on our initial work, presenting a more detailed experimental and numerical study of the characteristics and dynamics of soliton explosions in passively mode-locked fiber lasers. Specifically, we explore different cavity configurations and gain levels, observing and characterizing explosion events using spectral and temporal real-time single-shot techniques. Our results highlight that the explosion characteristics observed in experiments depend critically on the position in the cavity where the output coupler is located. Furthermore, we find that the probability with which explosions occur depends on the pump power. We also identify a new kind of “partial” explosion, where strong spectral interference fringes appear on the pulse spectra, but a full collapse is avoided. Finally, we perform numerical simulations based on a realistic iterative cavity map and obtain results that are in good qualitative agreement with experimental measurements. Careful analysis of the simulation results provides strong credence to the interpretation that soliton explosions can be linked to a multipulsing instability.