A new paper is out. Yan Feng, Luke R. Taylor, and Domenico Bonaccini Calia, “150 W highly-efficient Raman fiber laser,” Opt. Express 17, 23678-23683 (2009).
We report a more than 150 W spectrally-clean continuous wave Raman fiber laser at 1120 nm with an optical efficiency of 85%. A ~30 m standard single mode silica fiber is used as Raman gain fiber to avoid second Stokes emission. A spectrally asymmetric resonator (in the sense of mirror reflection bandwidth) with usual fiber Bragg gratings is designed to minimize the laser power lost into the unwanted direction, even when the effective reflectivity of the rear fiber Bragg grating becomes as low as 81.5%.
That is the laser we built to pump the 39 W narrow linewidth 1178 nm Raman fiber amplifier.