Enhancing free space optical communication with orbital angular momentum: a case study on multichannel multiplexing and signal reliability

Free Space Optical Communication (FSOC) is gaining attention as a reliable alternative to radio frequency (RF) systems, driven by the saturation of RF bands and advancements in optical technologies. FSOC offers higher bandwidth and secure, directional laser beams that are harder to intercept. However, ensuring reliable transmission remains challenging, especially in outdoor environments affected by atmospheric turbulence. This study presents an experimental FSOC system deployed over a 60-meter distance, exploring optical multiplexing through light-carrying Orbital Angular Momentum (OAM) to increase data rates. The research examines the system’s ability to perform multistate detection for reliable multiplexing, addressing key factors like power, signal-to-noise ratio, and bandwidth limitations. Additionally, a novel signal recovery method is proposed, based on pre-analysis of the system’s transient response, to optimize the correction algorithm and enhance performance under bandwidth constraints.