Structured Light in Turbulence

TLDR

Optical communication is essential to the modern economy, and structured light offers promising bandwidth increases, but free‑space transmission is limited by turbulence‑induced distortion. The paper reviews recent progress in structured light in turbulence, providing a tutorial summary of core concepts and highlighting state‑of‑the‑art, aiming to serve the free‑space optical communication community. The review is supported by experimental studies that identify optimal structured light types in turbulence, compare vector and scalar modes, analyze diversity–multiplexing trade‑offs, and exploit turbulence models for improved signal processing. The experiments show that certain structured light modes outperform others in turbulence, vector and scalar light behave differently, and that turbulence models can be leveraged to enhance optical signal processing.

Abstract

Optical communication is an integral part of the modern economy, having all but replaced electronic communication systems. Future growth in bandwidth appears to be on the horizon using structured light, encoding information into the spatial modes of light, and transmitting them down fibre and free-space, the latter crucial for addressing last mile and digitally disconnected communities. Unfortunately, patterns of light are easily distorted, and in the case of free-space optical communication, turbulence is a significant barrier. Here we review recent progress in structured light in turbulence, first with a tutorial style summary of the core concepts, before highlighting the present state-of-the-art in the field. We support our review with new experimental studies that reveal which types of structured light are best in turbulence, the behaviour of vector versus scalar light in turbulence, the trade-off of diversity and multiplexing, and how turbulence models can be exploited for enhanced optical signal processing protocols. This comprehensive treatise will be invaluable to the large communities interested in free-space optical communication with spatial modes of light.