Correlation between the dopant concentration and the anharmonicity of bending vibrations in silica optical fibers

The generation of high-order Stokes components in a silica optical fiber doped with germanium oxide to 10 and 45 mol % has been studied using a picosecond pulsed stimulated Raman scattering (SRS) technique. An increase in the dopant concentration leads to a decrease in the anharmonicity of bending vibrations in the fiber. It is suggested that the observed effect is related to an increase in the dissociation energy and force constants of the vibrating complexes.