In the past, an emphasis was placed on the research, design, and development of various infrared (IR) devices and systems primarily for military applications. The future trend, however, is towards the use of IR technology equally or with greater emphasis in the commercial sector. Both indoor and outdoor applications are possible. Commercial availability of special solid state diodes has opened the possibility of producing cost-effective laser atmospheric communication applications, for voice, data, and video. It is expected that infrared communications technology as a photonics field will have the impact of the major photonics field in the 21st century.