Abstract

The magnitude¹ and spectral dependence^2-4 of the Raman gain of silica glass were studied by a number of researchers twenty years ago. The results of those investigations have subsequently been used in investigations of the effect of Raman gain on pulse compression using optical fibers, and in designing fiber Raman lasers and amplifiers. Intra-pulse Raman effects, such as Kärtner’s⁵ recently proposed theory of noise generation in squeezing experiments using solitons and the soliton self-frequency shift,⁶ depend on the low frequency region of the gain spectrum. To assist further investigation of these effects, we present new measurements of the Raman gain spectrum from 10 cm ⁻¹ to 900 cm ⁻¹. In addition, we will describe observations of coherent excitation of low frequency inodes of the medium facilitated by our new experimental technique.

© 1994 Optical Society of America