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In this paper, we carry out a numerical study of supercontinuum generation (SCG) by propagating hundreds of noise-like pulses (NLPs), produced by a figure-eight laser (F8L) model, through different lengths of standard single-mode fibre (SMF). This work confirms the results of our previous experimental study (Lauterio-Cruz et al 2017 Laser Phys. 27 065107), highlighting the interest in using NLPs as a pump for SCG in cheap optical fibres. Using moderate peak powers (~100 W) we obtain broad and smooth SC spectra extending over hundreds of nm towards longer wavelengths. In order to simulate the fibre attenuation out of the telecommunication window, we propose a rudimentary approximation of the attenuation spectrum for SMF.

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.

In this work we browse an overview of the complex dynamics that arise in the non-stationary modes of operation of partly mode-locked fiber lasers under strict polarization control. Both ring and figure-eight cavities implementing saturable absorber mechanisms that rely on nonlinear polarization rotation were considered. The use of twisted fiber ensures robust operation, whereas precise polarization adjustments allow tailoring the nonlinear switching characteristic in a clear and repeatable manner. The enhanced flexibility of these sources allowed identifying and studying a broad spectrum of peculiar dynamics, in particular by implementing the temporal and spectral mapping techniques. These include the emergence, fusion, splitting, complex evolution and eventual decay of chaotic bunches of radiation, which are also subject to large spectral shifts, ample quasi-periodic instabilities, extreme-intensity events or the creation of solitons, among others, as well as the complex evolution of massively multiple soliton states. Finally, with the help of numerical simulation, several aspects of the physics underlying these puzzling behaviors could be elucidated.