Measurement techniques for the evaluation of photodarkening in fibers for high-power lasers

A setup for core-pumping of Yb-doped optical fibers has been developed to induce photodarkening and benchmark their suitability as a long-life active medium in high power fiber lasers for industrial applications. The measurements setup, its reliability and preliminary tests on PD affected and PD free fibers are here presented. Repeatability of measurements has also been carried out.