Development of a sensorless tracking system for fiber coupling

Abstract

Satellite communications provide global coverage by connecting remote and underserved areas where terrestrial networks are unavailable. In particular, free space optical communication offers significantly high data rates and very compact terminals, hence representing an increasingly relevant field of research. Accuracy and reliability are crucial for this technology, as an inaccurate tracking of the narrow incoming beam can result in data loss or significant signal fading at the receiver. The novel tracking system designed in this thesis aims to employ fiber coupling to precisely detect the direction of the incoming laser beam. Compared to other systems, this approach offers reduced mechanical complexity by eliminating the need for multiple movable components and using only a single camera for the initial coarse tracking. At first, an accurate optical design and an analysis of the tracking methods are performed. Afterwards, the optomechanical system is assembled, aligned, and tested according to GEO satellite parameters from literature. The experimental results from the setup demonstrate the effective operation of the fiber coupling technique as a tracking method, achieving satisfactory system efficiency. The tracking system shows a positive outcome and the final tests prove its ability to successfully follow a moving spot within the field of view, leaving open the possibility for further investigation and potential applications of this setup.