Few-Mode Fiber Coupling Efficiency for Free-Space Optical Communication

TL;DR

This paper presents a theoretical model for coupling efficiency in free-space optical communication using few-mode fibers, analyzing effects of atmospheric turbulence and jitter, and demonstrating improved bit-error rate performance over single-mode fibers.

Contribution

A novel theoretical coupling model based on Laguerre-Gaussian modes for optimizing few-mode fiber coupling in free-space optical links.

Findings

Coupling efficiency varies with atmospheric turbulence and jitter.

Optimal coupling geometry enhances efficiency.

Few-mode fibers outperform single-mode fibers in high SNR regimes.

Abstract

Few-mode fiber is a significant component of free-space optical communication at the receiver to obtain achievable high coupling efficiency. A theoretical coupling model from the free-space optical communication link to a few-mode fiber is proposed based on a scale-adapted set of Laguerre-Gaussian modes. It is found that the coupling efficiency of various modes behaves differently in the presence of atmospheric turbulence or random jitter. Based on this model, the optimal coupling geometry parameter is obtained to maximize the coupling efficiency of the selected mode of few-mode fiber. The communication performance with random jitter is investigated. It is shown that the few-mode fiber has better bit-error rate performance than single-mode fiber, especially in high signal-to-noise ratio regimes.