High power narrow linewidth LP11 mode fiber laser using mode-selective FBGs

Abstract

We demonstrated a high power Yb-doped fiber laser capable of delivering LP11 mode laser output. The oscillation of LP11 mode was realized by incorporating a pair of few-mode fiber Bragg gratings (FBGs), whose LP11 mode reflection peaks are matched with each other. The temperature-sensitivity of the FBGs was used to optimize the matching degree of the LP11 mode reflection peaks. Based on this configuration, over 50 W of LP11 mode output power with a linewidth of around 70 pm was obtained, which, to the best of our knowledge, is the highest power obtained in LP11 mode all-fiber lasers. Moreover, this laser possesses a certain stability; the standard deviation of whose output power is ~0.07% over a period of 300 s stability test. This work could provide a stable and high power LP11 transverse mode laser source for a wide range of applications.