Modeling of Mode Coupling in Multimode Fibers With Respect to Bandwidth and Loss

Abstract

A fast, accurate and simple field coupling model is presented which is capable of describing mode coupling effects due to bends and splices in multimode fibers with parabolic index profile as well as the coupling losses induced by this process. This model is validated numerically by comparing the results to the well-known coupled amplitude theory model yielding the same relative bandwidth increase behavior as long as the coupling losses are the same. It is shown, that the number of discrete segments used in this model can be reduced considerably as long as the coupling losses are kept constant. The effect of mode coupling on the differential group delay, mode dependent loss, bandwidth gain and impulse response width reduction are analyzed. It is shown that the relative bandwidth gain induced in MMF links induced by the coupling process is independent of fiber parameters or number of guided modes; it can be fully characterized by coupling induced losses. The model is compared to well-known results given by power coupling models and a good agreement is observed for high steady state loss values.