Gain performance of Nd-doped fiber in the range of 1050–1140  nm

In this work, we present the gain characteristics of a Nd-doped fiber (NDF) obtained through fiber amplification. The NDFs used include a highly doped 30/125 fiber and a low-doped 20/125 fiber. It was found that the gain spectrum range of the NDF can cover 1050–1140 nm. The main gain region was 1060–1135 nm, providing over 500 times small-signal amplification, with the laser peak energy ratio reaching 80% or more. At the long-wavelength edge of 1140 nm with a 50 mW seed injection, a 2.5 W output can be obtained, corresponding to an amplification factor of 50. The excellent gain performance will greatly change our traditional impressions of NDF and provide new insights for research on high-gain fiber materials in 1.1 µm fiber lasers.