Modelling of gain profiles and Raman lasing in TiO2/GeO2-doped silica fibres

Abstract

. We analyze Raman lasing bandwidth for TiO 2 -doped single-mode fibre as a function of pumping power, following from modelling of the gain profile, and compare it with that typical for an etalon Raman (GeO 2 -doped) fibre. The both Raman gain profiles are quantified using the spontaneous Raman cross-sections derived with an original spectroscopic method. Extremely high accuracy of the multimode Gaussian decomposition is obtained for the Raman gain profiles. As a result, the Raman gain profiles can be presented in analytical form. A threshold spectral Raman profile is introduced and the lasing bands in the both single-mode fibres are simulated numerically. We discuss also the advantages of TiO 2 -doped fibres as the active media for fibre Raman lasing and compare their characteristics with those of the other fibre types.