Determination of resonance frequencies in silica fiber using SRS gain

In this paper, a new approach for the determination of resonance frequencies of a material using stimulated Raman scattering is reported. A numerical model for nonlinear composite Raman susceptibility (CRS) is proposed considering the effect of molecular vibrations. The model considers four parameters for each molecular vibration, termed as quadruplets. Based on this CRS, the theoretical Raman gain in silica fiber is estimated. Genetic algorithm technique is used to find out the quadruplets, resonance frequencies in particular, by matching the estimated Raman gain with its experimental value. Eight optimized resonance frequencies are obtained for silica material.