Bandwidth of Adaptive Optics System in Satellite-Ground Coherent Laser Communication

Abstract

The influence of system bandwidth of adaptive optics system to communication performance is investigated for satellite-ground coherent opticscommunication. For a certain modes corrected by adaptive optics, the required servo bandwidth is obtained and the low earth orbit (LEO) satellite-ground laser links are compared with the geosynchronous (GEO) satellite-ground laser links. The results show that the LEO links require larger servo bandwidth than the GEO links. This is due to the high speed relative movement between the LEO and the ground station can generate vertical wind speed link. And the bandwidth requirement of adaptive optics system for LEO-ground link and zenith angle are inversely related. The relationship between the mixing efficiency LEO-ground coherent laser communication link, the adaptive optics system servo bandwidth and corrected modes is also studied. The results show that 200 Hz of close-loop bandwidth can meet the requirement, and increasing the number of actuators on deformable mirror is a more effective way to improve the mixing efficiency when the bandwidth reaches 100 Hz.