Abstract: Using a tapered waveguide Raman cell, the interaction region between the pumping laser beam and Raman media is increased. The power density decreased by the waveguide wall reflection is compensated by the narrowing of the tapered waveguide cross section. The Raman conversion efficiency is increased at some gas pressure of the Raman media. The uniformity of the first Stokes output is also improved by the tapered waveguide.