Raman or fluorescent scattering by active molecules or ions embedded in a single-mode optical fiber.

By considering active molecules or ions as a collection of induced oscillating dipoles, we treat the problem of Raman or fluorescent scattering by the active molecules or ions embedded in a single-mode optical fiber theoretically. The analytical expressions and the numerical results for the scattering coefficients and the even-odd mode conversion coefficients of the guided modes are given, based on the method of dyadic Green's functions and on the expansions of the modal fields in terms of the vector cylindrical wave functions. We expect to incorporate the treatments into the analysis of a rare-earth-doped fiber amplifier or a fiber Raman amplifier.