220 W Raman fiber laser at 1.24 μm based on phosphosilicate fiber

A Raman fiber laser with more than 220 W output at 1.24 μm with phosphorus-doped single-mode fiber as gain medium is reported. The laser consists of a 30 m long piece of fiber and a pair of fiber Bragg gratings with different bandwidth, pumped with a high power 1064 nm Yb fiber laser. The optical conversion efficiency is 64% and the slope efficiency is 71.4%. The full width half-maximum linewidth at the maximum output is 5.6 nm. To the best of our knowledge, the reported power is an order magnitude higher than previous reports in phosphosilicate fiber Raman laser.