Experimental Investigations on the TMI Thresholds of Low-NA Yb-doped single mode fibers

TL;DR

This paper investigates the mode instability thresholds of low-NA Yb-doped single mode fibers, demonstrating high-power outputs and analyzing factors like bend diameter and pump wavelength to optimize performance.

Contribution

It provides new experimental data on the power thresholds and effects of fiber parameters for Yb-doped fibers, including a novel fiber achieving higher power output.

Findings

Achieved 2.9 kW output power with optimized parameters.

Reported 4.4 kW single-mode power with a new fiber design.

Analyzed influence of bend diameter and pump wavelength on mode instability.

Abstract

In this contribution we investigate the transversal mode instability behavior of an ytterbium doped commercial 20/400 fiber and obtain 2.9 kW of output power after optimizing the influencing parameters. In this context, we evaluate the influence of the bend diameter and the pump wavelength within the scope of the absorption length and the length of the fiber. Furthermore with a newly developed fiber we report on 4.4 kW of single-mode output power at 40 cm bend diameter.