Multi-access laser terminal using liquid crystal beam steering

Abstract

Laser communications offer increased bandwidth and security over radio frequency. These advantages have made laser communications a key technology for future communication systems. The operation of transformational lasercom networks include terminal capabilities that are beyond those normally associated with one-to-one links. One requisite capability is multiaccess communication where one terminal communicates with several other terminals. This type of operation is important for any terminal that is acting as a hub for other terminals. Thus multiple optical communication links mimic broadcast communications in a more secure format. Also, multiaccess operation is desirable for dynamic routing schemes where several terminals in the field maintain multiple links to route around obstructions. A multi-access laser terminal offers potential savings in size, cost, and power, and is considered an enabling technology for the transformational satellite communications system (TSAT). A space platform for optical communications could benefit from nonmechanical beam steering in which no inertia is used to redirect the laser communications link. This benefit can be realized by compact, low-power, light-weight optical phased arrays. Non-mechanical beam steering eliminates the need for massive optomechanical components to steer the field of view of optical systems. A phased array approach also allows for random access beam steering. After a brief introduction to satellite-based laser terminal concepts, liquid crystal beam steering and how it might be used to implement a multi-access laser terminal is discussed. The paper ends with a summary