Femtosecond Optical Superregular Breathers

TL;DR

This paper explores femtosecond optical superregular breathers in fibers, revealing unique suppression states and nonlinear dynamics absent in longer picosecond regimes, confirmed through numerical simulations.

Contribution

It demonstrates the existence of half-transition and full-suppression SR breather states in femtosecond regimes, highlighting new nonlinear behaviors in optical fibers.

Findings

Full-suppression mode linked to zero growth rate of modulation instability

Robustness of SR modes confirmed in integrable and nonintegrable cases

Distinct dynamics compared to picosecond regime

Abstract

Superregular (SR) breathers are nonlinear wave structures formed by a unique nonlinear superposition of pairs of quasi-Akhmediev breathers. They describe a complete scenario of modulation instability that develops from localized small perturbations as well as an unusual quasiannihilation of breather collision. Here, we demonstrate that femtosecond optical SR breathers in optical fibers exhibit intriguing half-transition and full-suppression states, which are absent in the picosecond regime governed by the standard nonlinear Schr\"{o}dinger equation. In particular, the full-suppression mode, which is strictly associated with the regime of vanishing growth rate of modulation instability, reveals a crucial \textit{non-amplifying} nonlinear dynamics of localized small perturbations. We numerically confirm the robustness of such different SR modes excited from ideal and nonideal initial states in both integrable and nonintegrable cases.