Orbital Angular Momentum (OAM) Mode Mixing in a Bent Step Index Fiber in Perturbation Theory: Multiple Bends

TL;DR

This paper analyzes how multiple bends in a step-index fiber affect the propagation and mixing of orbital angular momentum modes, providing analytic expressions for crosstalk and mode intensity changes based on bend orientation.

Contribution

It extends previous single-bend analysis to multiple bends, deriving analytic formulas for mode crosstalk and intensity variations in complex fiber configurations.

Findings

Derived analytic expressions for OAM mode crosstalk in multiple bends.

Showed how bend orientation influences mode intensity patterns.

Quantified the impact of successive bends on mode mixing.

Abstract

In this paper, we address the impact of multiple fiber bends on orbital angular mode (OAM) mode propagation in a fiber. In particular, we extend the OAM mode-mixing due to a single-fiber bend studied earlier in detail for the step-index fiber, to the case of a succession of bends. The bends may have relative orientation with respect to each other. Analytic expressions leading to crosstalk are given. The OAM mode intensity at the output of a pair of bends is especially studied with emphasis on the intensity pattern changes that arise from the changes in the relative orientation of the bends.