Detection of Orbital Angular Momentum Modes via Spiral Phase Plate

TL;DR

This paper analyzes the effectiveness of spiral phase plates as low-cost, efficient detectors for orbital angular momentum modes, which are vital for increasing capacity in optical communication systems.

Contribution

It provides a thorough analysis of spiral phase plates as OAM detectors, including optimization of parameters for improved detection performance.

Findings

Inverse-SPP enables effective OAM detection

Optimized parameters improve efficiency and reduce crosstalk

Analytical and numerical methods validate detection performance

Abstract

Mode division multiplexing (MDM) systems leveraging spatial modes carrying orbital angular momentum (OAM) present a promising approach to enhance communication capacity in free-space and fiber-optic networks. Efficient detection of OAM modes is critical for their practical implementation. Spiral phase plates (SPPs) are low-cost optical elements with simple structures, capable of generating OAM waves with high conversion efficiency and precision. This makes the inverse-SPP a promising candidate for the detection of OAM modes. In this study, the performance of SPPs as OAM detectors is thoroughly analyzed. Key parameters, including efficiency, crosstalk, and signal-to-interference ratio, are examined through analytical and numerical methods. Results demonstrate that an inverse-SPP, combined with an optimized propagation length and aperture size, enables effective and precise OAM detection operation.