Analysis of guided optical eigenmodes in magneto-optical fibers with applications to OAM mode selective couplers

Abstract

Mode division multiplexing (MDM) technology can regard each eigenmode in optical fibers as an independent channel to carry different data information, helpful for improving the transmission capacity of optical fiber communication systems. The spatial distribution, state of polarization and propagation constant of guided optical eigenmodes in the magneto-optical (MO) fiber are derived theoretically by the analysis of linear polarization (LP) and exact modes. The transverse distribution of the eigenmodes in the MO fiber can be constructed by those of exact modes in the conventional fiber. The effect of applied magnetic field on the eigenmodes and their effective refractive indices is studied. Simulation results show that, the eigenmodes in the MO fiber may be represented by the pseudo-modes of circular polarization (CPlnR/L) or the true modes of orbital angular momentum (OAM±l,nR/L) when applied magnetic field is sufficiently large. The measurement method for weak magnetic field based on Stokes parameters is proposed. The magnetic tunability of OAM mode selective couplers (MSCs) is also analyzed.