Optical technologies for on-board processing of microwave signals

In the last decade, optics has proved a key technology for the transmission and handling of broadband signals in telecommunication networks. Future telecom satellite payloads will have to receive, process, route and re-transmit an increasing number of microwave signals. We have been investigating how the technologies inherited from terrestrial optical communications may bring substantial improvements or provide any breakthrough in satellite sub-systems. Optical technologies may contribute to the advent of new payload designs by enhancing or complementing conventional electronic functions, or by implementing new functions for which there is no satisfactory electronic solution. Critical issues such as EMC/EMI, RF isolation, mass, volume figures could be improved significantly as well. The investigated functions include optical distribution of high-frequency local oscillators (LO), optical frequency-conversion and optical cross-connection of microwave signals. Optical techniques can be used for distributing LO’s directly in the microwave or millimetre-wave range in many sub-systems of future payloads. They comply with low-phase noise requirements, while bringing drastic mass savings and suppressing isolation and EMC/EMI issues. However, it i