Trampolinelike pulsating soliton fiber lasers

Apart from stationary solitons originating from wave self-organization in ultrafast lasers, pulsating solitons have attracted lots of research interest due to their fantastic evolutionary behaviors, whose mechanisms are commonly dominated by dissipative effects such as gain, loss, and spectral filtering. Here, we demonstrate the trampolinelike pulsating soliton in the laser resonator originating from the conservative effects, i.e., Kerr effect and dispersion. It is found that the overdriven self-phase modulation induces the peak-to-dip transformation in the spectral domain, which is terminated by nonlinear spectral focusing due to the interplay between cross-phase modulation and anomalous dispersion. Such dynamic competition between the spectral broadening and focusing leads to the quasiperiodic peak-dip alternation with roundtrips like the trampoline game. A slow pulsation coexists with the trampolinelike fast pulsation due to the long-term soliton shaping. The simulation validates well experimental observations, fully revealing the underlying mechanism of the trampolinelike pulsating soliton. Having the potential to control laser stability, our results also show that the interplay between the Kerr effect and anomalous dispersion within laser cavities can trigger diverse transient phenomena in addition to the well-studied conventional soliton and modulation instability.