Dependence of Raman gain on relative index difference for GeO_2-doped single-mode fibers

Abstract
Raman gain has been measured for five single-mode fibers with different relative index differences up to 1.0%. Using an experimental equation relating the mode-field radius to the relative index difference, a simple and practical relation between the Raman gain and the relative index difference has been established. The Raman-gain constant for pure SiO2 has been evaluated to be 7.4 × 10−14 m/W.