Abstract

A few years ago a spectroscopic aspect of stimulated Raman scattering (SRS) in optical fibers was established¹. It is well-known, that in bulk nonlinear media the intense light wave is parametrically instable. As a consequence the SRS excitation may occur, but the most intensive vibration has a lowest SRS threshold and determines the spectral content of secondary radiation only. Due to the long interaction distance in an optical fiber even a small amount of scattered centers which include the bonds with enough hyperpolarizabilities takes part in the SRS process. Early the effective SRS by the local native microdefects and by the ones due to the dopant inclusion in silica network was observed¹. Later the SRS spectroscopic studies were spreaded on the colour photoinduced centers, which determined an effective second harmonic generation in silica fiber core².

© 1996 IEEE