Single-pass Raman generation pumped by a mode-locked laser

Single-pass Raman generation pumped by a mode-locked Nd:YAG laser is investigated for long-span and low-loss fibres. The peak wavelength of the first Stokes jumps dramatically from 1.114 ¿m to 1.12 ¿m at 1.65 W average input power. The first Stokes increases rapidly between the inputs of 1.65 W and 2.1 W. These characteristics of single-pass stimulated Raman scattering are discussed in terms of group velocity matching.