Splitting of levels in a circular dielectric waveguide

TL;DR

This paper demonstrates mode splitting in a circular graded-index optical fiber by solving Maxwell's equations, revealing how degeneracy is lifted by spin-orbit and tensor forces, with implications for optical resonator design.

Contribution

It provides a full Maxwell equation solution showing mode splitting due to spin-orbit and tensor effects in optical fibers, a novel analysis in this context.

Findings

Degeneracy of vortex Laguerre-Gauss modes is lifted.

Numerical estimations of group delays and frequency splitting are provided.

Mode splitting impacts optical fiber and resonator performance.

Abstract

A splitting of modes in a circular graded-index optical fiber is demonstrated by solving the full Maxwell equations using the perturbation analysis. It is shown that the degeneracy of vortex Laguerre-Gauss modes with distinct orbital angular momentum (OAM) and polarization (spin) but the same total angular momentum is lifted due to the spin-orbit (vector) and tensor forces. Numerical estimations of group delays of modes in optical fiber and frequency splitting in Fabry-Perot and ring resonators are presented.