Switching, explosion, and chaos of multi-wavelength soliton states in ultrafast fiber lasers

Abstract

Because of the complexity and difficulty of realizing a multi-wavelength soliton state, reports on its internal dynamic characteristics are scarce. In this study, the switching and periodic soliton explosion processes of the multi-wavelength soliton state in a negative dispersion passively mode-locked fiber laser are realized. The generation of the multi-wavelength soliton state undergoes the process of noise, oscillation, and stable mode-locking, and the splitting and annihilation of solitons with different group velocities directly impact the generation and disappearance of three wavelengths. Positive and negative dispersion lead to different group velocities of solitons. The presence and displacement of solitons with different group velocities cause soliton collisions, which lead to soliton explosions. A soliton experiences relative phase oscillation, chaos, and oscillation, as well as convergence and separation before and after an explosion. With an increase in parameters related to pump power, single-soliton oscillation, multi-wavelength solitons, and chaos are found in experiments and simulations, proving the relevance and reliability between simulation and experimental results. This work promotes the dynamical study of multi-soliton collisions in nonlinear science and the development of chaos theory in multi-comb lasers.