More than 200 W random Raman fiber laser with ultra-short cavity length based on phosphosilicate fiber

An over 200 W high-power first-order random Raman fiber laser (RRFL) at 1238 nm is demonstrated. The laser is based on a half-open cavity with a piece of 30 m phosphosilicate fiber. This RRFL is pumped by a conventional 1064 nm Yb-doped fiber laser. After suppressing the silica Raman component, a maximum output power of 206.7 W is obtained with a full width half-maximum linewidth of 7.1 nm at a pump power of 346.3 W, corresponding to an optical-to-optical efficiency of 59.7%. To the best of our knowledge, this is the highest reported output power of RRFL on the basis of phosphosilicate fiber with the shortest cavity length. (C) 2019 Optical Society of America