High-Capacity and Reliable Free-Space Optical Communication Systems

Dear Colleagues,

Free-space optical (FSO) communication stands at the forefront of emerging 6G and space–air–ground integrated networks (SAGINs). With ultra-high data rates, license-free bandwidth, and fast deployment, FSO enables a wide range of applications from terrestrial backhaul to aerial platforms and satellite–ground laser links. While FSO offers immense bandwidth and high directionality, its practical implementation faces a dual bottleneck. First, atmospheric turbulence and pointing errors jeopardize link stability. Second, and equally critical, the reliability of optical links must be considered together with communication security. Despite the directional nature of FSO, the open propagation environment and inevitable beam divergence may expose signal footprints to potential eavesdropping, motivating physical-layer security-aware designs that jointly balance secure transmission and reliable connectivity.

This Special Issue, titled “High-Capacity and Reliable Free-Space Optical Communication Systems”, aims to gather cutting-edge research on building systems that are robust against environmental impairments and secure against potential attacks. We welcome contributions on physical-layer security (PLS) and secrecy performance analysis, alongside reliability-enhancing techniques such as hybrid FSO/RF architectures, reconfigurable intelligent surfaces (RIS), and relay-assisted transmission. Furthermore, studies on advanced modulation and detection, deep learning for channel estimation, and satellite–ground optical communications are highly encouraged. By integrating reliability optimization with security-aware design, this Special Issue seeks to advance the development of high-capacity, stable, and secure optical wireless networks.

Prof. Dr. Yi Wang
Prof. Dr. Guanjun Xu
Dr. Guowei Yang
Guest Editors

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