Real-time temporal-spectral analysis of complex dynamics involving multiple soliton states in a dual-wavelength passively mode-locked fiber ring laser

Abstract

We present an experimental study of complex dissipative solitons dynamics in a passively mode-locked fiber ring laser. Recently, thanks to real-time spectroscopy techniques such as the dispersive Fourier transform (DFT), it has been possible to study the complex internal dynamics of soliton molecules. However, most of the works have been limited to the study of intermolecular or intramolecular dynamics involving a small number of solitons within a single compact soliton packet, to which the DFT technique applies naturally. In this work, we study the dynamics of complex arrangements of multiple solitons, extending the analysis to regimes where multiple soliton packets at different wavelengths coexist and interact in the cavity, probing simultaneously the internal dynamics of various short-lived soliton molecules, as well as the collective dynamics of the different soliton packets distributed in the cavity, all of which is made possible by simultaneous analysis in the temporal and spectral domains. This allows to relate temporal dynamics at different time scales, as well as temporal and spectral events. In particular, we report the experimental observation of the dynamics of the Kelly sidebands that flank the soliton spectra, and relate it to temporal and spectral events such as extinctions of soliton packets with pulsating amplitude, spectral narrowing, and with energy fluctuations.