Developing spatiotemporal solitons in step-index multimode fibers

TL;DR

This paper demonstrates the generation of spatiotemporal solitons in step-index multimode fibers using gain-mediated nonlinear dynamics, enabling stable pulse propagation with potential applications in optical communications and laser technology.

Contribution

It introduces a novel method for realizing stable spatiotemporal solitons in multimode fibers through gain competition and energy redistribution among modes.

Findings

Successful mode-locking of spatiotemporal solitons in multimode fibers.

Gain-mediated nonlinear dynamics stabilize pulse shape during propagation.

Potential applications in multi-channel communications and high-power fiber lasers.

Abstract

Spatiotemporal solitons (STSs) are localized solitary waves in both space and time that involve complex linear and nonlinear processes. Optical STSs have been observed in various media, but they are difficult to be realized in multimode fibers due to their large modal dispersion. Here, we report STS mode-locking and spatiotemporal nonlinear dynamics in a step-index multimode fiber mediated by gain. Gain competition and energy redistribution among different spatial modes help nonlinearity effectively cancel both temporal splitting and spatial diffracting of the entire pulse (multicomponent soliton) and thereby maintain its shape during propagation. Optical STSs in multimode fibers therefore open a new way to clarify the fundamental science of spatiotemporal solitary waves and also imply important applications in multi-channel communications, optical switches and mode-area power scaling of fiber laser pulses.