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arXiv · 2603.05850

Unified model for breathing solitons in fibre lasers: Mechanisms across below- and above-threshold regimes

Ying Zhang·Bo Yuan·Junsong Peng·Xiuqi Wu·Yulin Sheng·Yuxuan Ren·Christophe Finot·Sonia Boscolo·Heping Zeng
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Abstract

The emergence of breathing solitons in mode-locked lasers presents a fundamental challenge for the theoretical modelling of mode locking, with the mechanisms underlying below- and above-threshold breathing solitons, and the origins of their distinct nonlinear dynamics, remaining poorly understood. Here, we develop a model that incorporates both spatial and temporal gain dynamics, enabling us to elucidate the origins of these two classes of pulsating states. We show that below-threshold breathing solitons arise from the interplay between Q-switching and soliton shaping, whereas Kerr nonlinearity and dispersion dominate the formation of above-threshold breathers. The model further captures the markedly different dynamical properties of these regimes. Experimental observations corroborate the simulations, validating the predictive power of the framework. Beyond providing a refined theoretical basis for ultrafast laser design, this work advances the broader understanding of non-equilibrium dynamics in mode-locked lasers and offers new perspectives on breathing soliton phenomena across diverse physical systems.

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Ying Zhang, Bo Yuan, Junsong Peng, Xiuqi Wu, Yulin Sheng, Yuxuan Ren, Christophe Finot, Sonia Boscolo, Heping Zeng. 2026-03-06. Unified model for breathing solitons in fibre lasers: Mechanisms across below- and above-threshold regimes. https://arxiv.org/abs/2603.05850

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