Spatiotemporal dissipative solitons and vortices in a multi-transverse-mode fiber laser

TL;DR

This paper models spatiotemporal mode-locking in multimode fiber lasers using a (3+1)D complex Ginzburg-Landau equation, revealing stable solitons and vortices, and identifying bistability phenomena.

Contribution

It introduces a novel (3+1)D model for multimode fiber laser dynamics, analyzing stability and interactions of various nonlinear modes including vortices.

Findings

Stable fundamental solitons and breathers identified.

Vortices with winding number n=1 are stable, n=2 are unstable.

Bistability between fundamental and vortex solitons observed.

Abstract

We introduce a model for spatiotemporal modelocking in multimode fiber lasers, which is based on the (3+1)-dimensional cubic-quintic complex Ginzburg-Landau equation (cGLE) with conservative and dissipative nonlinearities and a 2-dimensional transverse trapping potential. Systematic numerical analysis reveals a variety of stable nonlinear modes, including stable fundamental solitons and breathers, as well as solitary vortices with winding number $n=1$, while vortices with $n=2$ are unstable, splitting into persistently rotating bound states of two unitary vortices. A characteristic feature of the system is bistability between the fundamental and vortex spatiotemporal solitons.