Stimulated Raman scattering in high-power double-clad fiber lasers and power amplifiers

Theoretical analyses of stimulated Raman scattering (SRS) in high-power ytterbium-doped double-clad fiber lasers and power amplifiers with bidirectional end pump and distributed pump are comprehensively presented. The Raman effects are quantitatively compared in these schemes with different fiber lengths, core diameters, signal wavelengths, pump absorption, facet reflections, etc., and the related restrictions are also illustrated. Fiber power amplifiers, characteristically with low facet reflections, have the advantage of significantly higher SRS thresholds than fiber laser resonators, which makes master oscillator power amplifiers better candidates for kilowatt single-transverse-mode fiber laser sources. (c) 2005 Society of Photo-Optical Instrumentation Engineers.