Numerical modelings of ultrashort pulse propagation and conical emission in multimode optical fibers

Abstract

We make use of two well-known numerical approaches of nonlinear pulse propagation, namely, the unidirectional pulse propagation equation and the multimode generalized nonlinear Schrödinger equation, to provide a detailed comparison of ultrashort pulse propagation and possible conical emission in the context of multimode optical fibers. We confirm the strong impact of the frequency dispersion of the nonlinear response on pulse splitting and supercontinuum dynamics in the femtosecond regime for pumping powers around the critical self-focusing threshold. Our results also confirm that the modal distribution of optical fibers provides a discretization of conical emission of the corresponding bulk medium (i.e., here fused silica). This study also provides some criteria for the use of numerical models, and it paves the way for future nonlinear experiments in commercially available optical fibers.