Multimode optical fiber beam-by-beam cleanup

TL;DR

This paper demonstrates an all-optical beam switching method in graded-index multimode fibers, using nonlinear coupling to improve beam quality, with potential applications in high-power beam delivery and fiber lasers.

Contribution

It introduces a novel all-optical beam switching technique in multimode fibers using nonlinear coupling, validated by experimental mode decomposition.

Findings

Weak control beams can significantly improve beam quality.

Experimental validation confirms the effectiveness of the switching method.

Potential for high-power beam applications.

Abstract

We introduce and experimentally demonstrate the concept of all-optical beam switching in graded-index multimode optical fibers. Nonlinear coupling between orthogonally polarized seed and signal beams permits to control the spatial beam quality at the fiber output. Remarkably, we show that even a weak few-mode control beam may substantially enhance the quality of an intense, highly multimode signal beam. We propose a simple geometrical representation of the beam switching operation, whose validity is quantitatively confirmed by the experimental mode decomposition of the output beam. All-optical switching of multimode beams may find important applications in high-power beam delivery and fiber lasers.