Steady-state thermo-optic model of a continuous-wave Raman laser

We present a model of a cw Raman laser that includes thermo-optic effects that are due to the heating that is inherent in Raman conversion. Thermal lensing and thermal index gratings at high output powers are addressed. With a quadratic duct model we show that broadening of the spatial modes is evident at low Stokes output powers and that accounting for thermal lensing in the laser design can significantly enhance the conversion efficiency. The model agrees with experimental results from a cw H-2 Raman laser and allows for the design of high-power and solid-state cw Raman lasers. (C) 2002 Optical Society of America.