Nonlinear dynamics in multimode optical fibers

TL;DR

This paper reviews recent progress in understanding nonlinear phenomena in multimode optical fibers, including Kerr-induced beam self-cleaning, spectral sideband generation, and supercontinuum production, highlighting their underlying mechanisms and potential applications.

Contribution

It provides a comprehensive overview of recent experimental and theoretical advances in spatiotemporal beam shaping and nonlinear effects in multimode optical fibers.

Findings

Kerr-induced beam self-cleaning redistributes energy into a fundamental-like mode.

Spectral sidebands are generated through phase matching during self-imaging.

Supercontinuum spanning visible to mid-infrared is achieved in multimode fibers.

Abstract

We overview recent advances in the research on spatiotemporal beam shaping in nonlinear multimode optical fibers. An intense light beam coupled to a graded index (GRIN) highly multimode fiber undergoes a series of complex nonlinear processes when its power grows larger. Among them, the lowest threshold effect is the Kerr-induced beam self-cleaning, that redistributes most of the beam energy into a robust bell-shaped beam close to the fundamental mode. At higher powers a series of spectral sidebands is generated, thanks to the phase matching induced by the long period grating due to the periodic self-imaging of the beam and the Kerr effect. Subsequently a broadband and spectrally flat supercontinuum is generated, extending from the visible to the mid-infrared.