Fast-Steering Prism for correction of Tip Tilt aberrations

Free-space optical communication systems always require a precise focusing on the receiver to maximize the fiber coupling efficiency. Unfortunately, atmospheric turbulence causes scintillation at the receiver. Ground to ground receivers over short distances (up to 500m) have usually small aperture (about 50mm). In this case the main aberration is tip/tilt and its correction is of fundamental importance for high bandwidth data transmission. We present a new concept of Fast Steering Prism (FSP) for the correction of tilt, suitable for optical communication and optical tracking. The system consists in the use of a novel design of a tunable prism with a variable angle based on the usage of piezoelectric actuators. A system with a FSP has the advantage to be more compact and simpler with respect to the one with a fast-steering mirror. The entire setup has been tested in a 200m outdoor transmission with promising results.