Research on telescope array for inter-satellites laser communication

Abstract

Recent years have seen an explosive increase in the application of inter-satellites laser communication system. Considerations make phased arrays an attractive target for optical communication applications. This paper proposes a novel telescope array for inter-satellites laser communication and investigates phased telescope arrays to be employed in receive terminals of free-space laser inter-satellites communication links. Potential advantages over single monolithic telescopes consist in non-mechanical adaptive fine pointing of the mainlobe and a reduction of terminal volume, mass and cost. First, the basic function, the interfaces, and the performance parameters of one telescope are given. Next, the structure of a receive telescope array are described, and then the performance parameters of this telescope array are discussed. The different performances including antenna gain and pattern of optical antenna and telescope array in inter-satellites laser communication system are given in this part. A quantitative assessment reveals that arrays using coaxial beam superposition are best suited for optical data communications. Based on this finding, the main characteristics of superimposing telescope arrays are calculated. And calculations prove that, in practical applications, telescope array has better performance than one telescope used in laser inter-satellites communication, and even more, the influence of incoherent background radiation is negligible. The analyses results show that smart antenna is better than optical antenna in this communication system. In many important aspects of phased array design, we will consider 1) Frequency Synchronization and 2) Beam steering as being of primary importance to the present analysis. Frequency synchronization is necessary for proper beam spatial coherence, while beam steering is critical to how this cohered beam is pointed in a desired direction. We will address system performance and implementation aspects of both issues in fiber optic control. Three basic architectures for beam steering control via optics have been reported and proposed.