Invented more than a hundred years ago by Alexander Graham Bell, the technology of free-space optical communications, or lasercom, has finally reached the level of maturity required to meet a growing demand for operational multi-giga-bit-per-second data rate systems communicating to and from aircrafts and satellites. Putting the emphasis on near-earth links, including air, LEO, MEO, and GEO orbits, Near-Earth Laser Communications presents a summary of important free-space laser communication subsystem challenges and discusses potential ways to overcome them. This comprehensive reference provides up-to-date information on component and subsystem technologies, fundamental limitations, and approaches to reach those limits. It covers basic concepts and state-of-the-art technologies, emphasizing device technology, implementation techniques, and system trades. The authors discuss hardware technologies and their applications, and also explore ongoing research activities and those planned for the near future. The analytical aspects of laser communication have been covered to a great extent in several books. However, a detailed approach to system design and development, including trades on subsystem choices and implications of the hardware selection for satellite and aircraft telecommunications, is missing. Highlighting key design variations and critical differences between them, this book distills decades’ worth of experience into a practical resource on hardware technologies.