Random distributed feedback fiber laser at 2.1 μm.

Abstract

We demonstrate a random distributed feedback fiber laser at 2.1μm. A high-power pulsed Tm-doped fiber laser operating at 1.94μm with a temporal duty ratio of 30% was employed as a pump laser to increase the equivalent incident pump power. A piece of 150m highly GeO2-doped silica fiber that provides a strong Raman gain and random distributed feedbacks was used to act as the gain medium. The maximum output power reached 0.5W with the optical efficiency of 9%, which could be further improved by more pump power and optimized fiber length. To the best of our knowledge, this is the first demonstration of random distributed feedback fiber laser at 2μm band based on Raman gain.