System Test Bed for demonstration of the optical space communications feasibility

The use of laser diodes for optical communications between satellites is the object of the European SILEX programme funded by ESA for which MATRA is prime contractor. As a step towards the development of a full scale space system, a complete System Test Bed (STB) dedicated to optical space communication feasibility demonstration has been built on ground. It uses functional breadboards of all key equipments required for an optical terminal. Communication and pointing functions have been studied and evaluated, both at subsystem and at terminal level. At system level a complete link includes two terminals one of which is a simulator fed with a characterization derived from the subsystem and terminal experiments. After a description of the STB principle, the paper presents test results and compares them to theoretical calculations.