Full-field real-time characterization of creeping solitons dynamics in a mode-locked fiber laser

Creeping solitons, which belong to the class of pulsating solitons, can be meaningful for fundamental physics owing to their fruitful nonlinear dynamics. Their characteristics in mode-locked lasers have been studied theoretically, but it is difficult to experimentally observe evolution dynamics in real time. Here, we have experimentally observed the temporal and spectral evolution dynamics of creeping solitons in a passively mode-locked fiber laser by employing time-lens and dispersive Fourier transform technique. With the aid of Raman amplification, the measured recording length of the time lens in the asynchronous mode could be substantially improved. Temporal soliton snaking motion and spectral breathing dynamics are experimentally obtained, confirming intrinsic feature of pulsation dynamics. These results display how single-shot measurements can offer new insights into ultrafast transient dynamics in nonlinear optics.