This book provides a comprehensive and systematic investigation into the theoretical and practical challenges of establishing reliable deep space optical communication links during superior solar conjunction, a critical period when signals must propagate through the highly turbulent solar corona. Targeting researchers, engineers, and graduate students in aerospace engineering, optical communications, and space science, the book addresses a fundamental bottleneck in deep space exploration: severe signal degradation caused by coronal plasma turbulence. The main topics encompass the physical modeling of the coronal environment, including non-Kolmogorov turbulence spectra and solar wind plasma dynamics. It presents a unified analytical framework for characterizing optical wave propagation impairments such as intensity scintillation, phase fluctuations, and angle-of-arrival variations. The text includes a comprehensive performance evaluation of single-link systems under various modulation schemes, such as PPM and hybrid LP-PM MSK-SIM, as well as the design of advanced relay-assisted architectures, including mixed RF/FSO and dual-hop FSO systems. These topics are critically important because deep space missions require exponentially higher data rates for scientific payloads, while traditional radio frequency links are approaching fundamental bandwidth and power limitations. The central problem this book addresses is the absence of a unified, physically accurate framework to predict and mitigate the effects of coronal turbulence, offering both theoretical foundations and practical design guidelines. This work facilitates the development of high-reliability, high-capacity optical links during solar conjunction, thereby supporting future human and robotic exploration of the solar system.

Guanjun Xu is a professor in the Space Information Research Institute, Hangzhou Dianzi University, China. He received his Ph.D. degree in information and communication engineering from Harbin Institute of Technology, China. After that, he was an associate professor and full professor at East China Normal University, China until 2023. His research interests include satellite communication, optical communication, channel modeling, and performance optimization.

Yulong Zhu is working toward the Ph.D. degree in electronic science and technology with the Space Information Research Institute, Hangzhou Dianzi University, Hangzhou, China. His current research interests include inter-satellite optical communication channel analysis, satellite micro-vibration suppression, and performance optimization of inter-satellite optical communication systems.

Lina Zhu received the Ph.D. degree in traffic science and communication engineering from Beihang University, Beijing, China, in 2022. Since 2022, she has been with the Space Information Research Institute, Hangzhou Dianzi University, Hangzhou, Zhejiang, China, as a Lecturer. Her current research interests include wireless communications, including satellite communications and non-orthogonal-multiple-access (NOMA) systems.

Weidang Lu received the Ph.D. degree in information and communication engineering from Harbin Institute of Technology in 2012. He is currently a Professor with the College of Information Engineering, Zhejiang University of Technology, Hangzhou, China. His current research interests include UAV communication, secure communication, and mobile edge computing.