The Optical Communications Demonstrator is a laboratory-based lasercom demonstration instrument designed to validate effective beacon acquisition, high bandwidth tracking, precision beam pointing, and point ahead compensation functions. The instrument is designed using an array detector for both spatial acquisition and high bandwidth tracking, and a fiber coupled laser transmitter. The array detector tracking concept provides wide field of view acquisition as well as high update rate using a single output channel device. At the same time, it permits effective platform jitter compensation and point ahead control using only one steering mirror. The use of fiber coupled transmitter further modularizes transmitter design and decouples the thermal management problem. The reduction in design complexity can lead to a reduced system cost and an improved system reliability. Furthermore, it can permit the implementation of a new generation of lasercom instruments capable of realizing the inherent advantages of optical frequency communication systems.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.