Abstract

Raman amplification was demonstrated in the early 1970s, but the invention of erbium-doped fiber amplifiers (EDFA) overshadowed the interest in it. Today, Raman scattering has again become a competitive approach for optical amplification because it is only restricted by the pump wavelength and Raman active modes of the gain medium. Pure-silica and germanium-doped silica fibres, currently utilized as Raman gain media in telecommunications, have quite low Raman gain coefficients and a limited usable spectral bandwidth of approx. 5 THz. Therefore, the investigation of materials possessing both large Raman gain coefficients and broader spectral bandwidth than fused silica is becoming necessary to satisfy the increasing telecommunications demands.

© 2009 IEEE