Impact of the refractive index profile on nonlinear effects in multimode fibers

Abstract:
We study the impact of fiber parameters such as the core radius and the numerical aperture on nonlinear effects in multimode fibers with graded-index profile. Furthermore, we investigate the influence of an additional trench on the nonlinear coupling factors. We calculate the mode fields of the guided eigenmodes and determine the overlap of the spatial field distributions. Based on this information, the coupling factors kuv can be calculated, representing a measure of the nonlinear coupling between different modes. While the choice of the refractive index profile is primarily used to influence the linear coupling characteristics or the group velocities of the different modes, we evaluate the impact on the overlap of these modes and hence the strength of intermodal and intramodal nonlinear effects.