Applications for optical free space links in inter-satellite and intra-satellite communications

Free space links between satellites provide a means of introducing increased connectivity into a satellite system. This can result in enhanced traffic capacity and extended coverage for the telecommunication systems and real-time relay of instrument data to the ground for Earth observation missions. Optical links offer the potential advantages over microwave links of lower mass, power and reduced size so that they can be accommodated more easily on the satellite. Matra Marconi Space has developed a range of optical terminals targetted at future inter-satellite requirements. This paper presents the current status of these optical terminals. Free space links also have potential for applications within the satellite itself. Intra-satellite links are required to connect subsystems within the payload. This is typically achieved using semi-rigid coaxial cables but the trend towards satellites with increased capacity and high gain multibeam antennas makes optical intra-satellite links attractive due to the increased connectivity and flexibility, signal routing, switching and distribution which can be achieved within the payload. An overview of potential intra-satellite applications is presented