Bidirectional Soliton Rain Dynamics Induced by Casimir-Like Interactions in a Graphene Mode-Locked Fiber Laser

TL;DR

This paper investigates the complex bidirectional dynamics of dissipative optical solitons in a graphene mode-locked fiber laser, emphasizing the role of long-range Casimir-like interactions in pulse behavior.

Contribution

It combines experimental and theoretical analysis to reveal how Casimir-like interactions influence soliton rain dynamics in fiber lasers, a novel insight into ultrafast laser physics.

Findings

Pulse bunches exhibit acceleration and bidirectional motion.

Drift speed and direction depend on bunch size and position.

Good agreement between model predictions and experimental observations.

Abstract

We study experimentally and theoretically the interactions among ultrashort optical pulses in the soliton rain multiple-pulse dynamics of a fiber laser. The laser is mode-locked by a graphene saturable absorber fabricated using the mechanical transfer technique. Dissipative optical solitons aggregate into pulse bunches that exhibit complex behavior, which includes acceleration and bi-directional motion in the moving reference frame. The drift speed and direction depend on the bunch size and relative location in the cavity, punctuated by abrupt changes under bunch collisions. We model the main effects using the recently proposed noise-mediated pulse interaction mechanism, and obtain a good agreement with experiments. This highlights the major role of long-range Casimir-like interactions over dynamical pattern formations within ultrafast lasers.