Fiber guided mode analyses and conversion using superposed helical gratings

TL;DR

This paper investigates how superposed helical gratings in optical fibers can generate and convert various guided modes, enhancing understanding of modal interactions and potential applications in fiber optics.

Contribution

It introduces a detailed analysis of mode conversion using superposed helical gratings, covering both low and high contrast index fibers, advancing modal control techniques.

Findings

Mode conversion is achievable with superposed helical gratings.

Analysis covers both low and high index contrast fibers.

Enhanced understanding of fiber guided mode interactions.

Abstract

Optical fibers can support various modal forms, including vector modes, linear polarization (LP) modes, and orbital angular momentum (OAM) modes, etc. The modal correlation among these modes is investigated via Jones matrix, associated with polarization and helical phase corresponding to spin angular momentum (SAM) and OAM of light, respectively. We can generate different modal forms by adopting superposed helical gratings (SHGs) with opposite helix orientations. Detailed analysis and discussion on mode conversion is given as for mode coupling in optical fibers with both low and high contrast index, respectively. Our study may deepen the understanding for various fiber guided modes and mode conversion among them via fiber gratings