120 W high-gain 1120 nm Nd-doped fiber laser

Abstract

In this work, we present a high-gain Nd-doped fiber (NDF) amplifier delivering up to 121 W at 1120 nm with a gain coefficient of 20.4 dB. The slope efficiency is 37.5 %, and the energy ratio of ASE from 1060 nm to 1100 nm is only 0.6 %. This excellent gain performance is attributed to the luminescence enhancement of iodine-doped NDF, which enhances emission in the range of 1090 nm – 1150 nm while reducing emission intensity deference between them and the 1060 nm peak, thus effectively avoiding the parasitic oscillation at 1060 nm. The NDF addresses the issue of the low gain in Yb-doped fibers at 1120 nm and will provide a new gain fiber choice for research on single-frequency fiber lasers and ultrafast fiber lasers in the 1100 nm band.