A review of operational laser communication systems

Laser communication systems which have been built into serviceable units are reviewed. Although systems built prior to 1965 were more of a breadboard nature, some early experiments of historical interest are described. After 1965, techniques and component reliability were sufficiently improved to permit the development of several interesting and sophisticated systems. Performance characteristics of the more representative of these systems are listed. Recent trends show the use of infrared wavelengths, injection lasers, mode-locked/pulse-code modulation systems, optical heterodyne detection, and automatic pointing and tracking.