A temporal insight into the rich dynamics of a figure-eight fibre laser in the noise-like pulsing regime

Abstract

We report on the dynamics of noise-like pulses at the ns scale in a passively mode-locked fibre laser, which grow in complexity as wave retarder adjustments are performed. We can observe that the laser operating in the fundamental mode can be tuned to get different shapes of the noise-like pulse. Following a regime of a very stable waveform, regimes characterized by a much more variable (but still compact) waveform are observed. Then we can get the fragmentation of the main bunch and expulsion of sub-packets and, finally, a variety of puzzling dynamics with increasing complexity are evidenced. Although the collective behaviour of the multiple waveforms is at first sight random we can observe some well-defined patterns in the kinematics of light bunches at the global cavity scale. These results may be useful to unravel the subtle mechanisms at play in complex dissipative nonlinear systems such as passively mode-locked fibre lasers.

Generation of spatio-temporal extreme events in noise-like pulses NPE mode-locked fibre laser

“…Similar approaches are used to study generation of passive cavity solitons [22,23], writing and erasing of topological solitons [24], interaction of multiple vectorial dissipative solitons in a vertical-cavity surface-emitting laser, [25], studies of rain of solitons in passively mode-locked fibre laser [26], soliton explosion in passively mode-locked fibre laser [27,28], generation of coherent structures in quasi-CW lasers [29][30][31]. Recent experimental studies of spatio-temporal dynamics of noise-like pulses include observation of various stable and unstable regimes [32], and Q-switched like soliton bunches [33].…”

Principles of operation of a passively mode-locked fiber ring laser and 3D mapping of ultra-short pulses

“…The behavior in time domain tends to present one pulse or a group of pulses with fixed temporal position over successive roundtrips, whereas the pulses associated with the other spectral component presents a temporal walk-off to the left or right. Besides, when only one spectral component exist, the 3D mapping measurement only shows pulses with fixed position over successive round-trips, as it can be observed for example in [34]; or in this case all pulses present a fixed temporal walk-off, as shown in [45]. This analysis is the essence and results of the reference [46].…”

“…Different behaviors and interactions of pulses have been investigated, which encompass different types of pulses: noise-like pulses (NLPs) [6,25,26,28], dissipative solitons [30,31], spiny solitons [32], among others. A recently developed tool, which is useful in ML-FL researches, is a 3D mapping technique of the pulse temporal profile, which helps analyzing pulse dynamics [31,[33][34][35][36].…”

Experimental study of non-stationary operation of a dual-wavelength passively mode-locked fibre ring laser

“…NLPs [32][33][34][35][36] are ∼ns-long packets containing hundreds or thousands of chaotic sub-pulses and present a broad optical spectrum [37,38]. In general, the NLPs present a complex dynamics that also corresponds to non-stationary regimes [31,[39][40][41]. This paper is structured in four sections.…”

“…The identification of NLP is made through the spectrum in figure 6(a), with the NLP component centred at 1531 nm (blue line) presenting a smooth trace (free of Kelly sidebands). The typical spectrum of a single NLP is actually very complex and presents a spurious aspect [37,38,40,41], and the smooth trace observed in figure 6(a) is due to the fact that the OSA presents the average of a large amount of individual traces, so that the fluctuations are averaged out.…”