Generation of 10.5 W, 1178 nm Laser Based on Phosphosilicate Raman Fiber Laser

The phosphorous-doped Raman fiber laser fabricated based on a Fabry-Perot cavity is demonstrated. The fiber length (L) values of 300 m and 700 m, and the reflectivity (R) values of the output fiber Bragg grating (FBG) of 15%, 30% and 50% are adopted. Under the optimum configuration of L=300 m, and R=15%, a 10.5 W, 1178 nm laser is obtained. Considering the pump power of 19.2 W, the optical-optical conversion efficiency is 54.7% and the corresponding slope efficiency is 80%. The 1178 nm light is frequency-doubled to generate 589 nm light as a source for the laser guide star (LGS) for the mesospheric sodium layer.