Multiple-vibrational-mode model for fiber-optic Raman gain spectrum and response function

We describe a model for the stimulated Raman gain spectrum and the Raman response function in silica fiber using multiple vibrational modes. We base the model on previous spectroscopic data [J. Opt. Soc. Am. B 1, 652 (1984) and J. Opt. Sec. Am. B 6, 1159 (1989)] and extend an earlier proposed model [Appl. Opt. 21, 359 (1982)] by making use of an inhomogeneous distribution of damped oscillators. The model provides a simple analytical expression for the Raman response function and an expression for the Raman gain spectrum that is easy to evaluate numerically. (C) 2002 Optical Society of America.