Optical Phased Array Improves Liquid Crystal Devices Used in Laser Beam Steering Subsystems

Under a DARPA program known as Steered Agile Beams (STAB), novel liquid-crystal devices are being developed by Rockwell Scientific Company (RSC) to enable compact, high-speed laser beam steering subsystems for applications in free-space laser communications over distances ranging from 1 to 100 km. For such distances, the subsystem must have precise control of the laser beam to account for atmospheric effects or any slight movements in the transmitting or receiving stations. This allows for high data rate communications between link partners without interruptions. Critical for this task is a device that can steer light continuously at a high rate of speed (approximately 1 kHz). A key element in the multistage architecture of this project is a liquid-crystal optical phased array (OPA) that requires a large number of high-precision synchronized analog outputs.