Study of wavelength dependence of mode instability based on a semi-analytical model

TL;DR

This paper presents a semi-analytical model to analyze how wavelength choices affect mode instability in high power fiber lasers, highlighting the roles of pump/seed wavelength and photodarkening in MI suppression.

Contribution

It introduces an improved semi-analytical model to study wavelength dependence of mode instability, including effects of photodarkening and strategies for MI suppression.

Findings

Wavelength selection influences MI threshold significantly.

Photodarkening can markedly reduce MI threshold.

Optimal pumping/seeding wavelengths can suppress MI effectively.

Abstract

We present theoretical study of wavelength dependence of mode instability (MI) in high power fiber lasers, which employs an improved semi-analytical theoretical model. The influence of pump / seed wavelength and photodarkening on threshold has been studied. The results indicate promising MI suppression through pumping or seeding at an appropriate wavelength. Small amounts of photodarkening can lead to significant impact on MI.