Optical interconnects for satellite payloads: sizing up the state of the art

Abstract

Broadband communication services such as high-definition TV, video on demand, and Triple Play are fueling the bandwidth appetite of individual subscribers and network-service providers. Satisfying this hunger requires a steady increase in total available bandwidth for terrestrial networks, most effectively using optical fiber. In fact, today optical fiber is the main trunk for all data traveling long distance in wideand local-area networks. Furthermore, individual customers can benefit from the huge data capacity of optical fiber by deployment of fiber to the home. Operators in the satellitetelecommunication sector face similar challenges driven by the same bandwidth demand as their terrestrial counterparts. Moreover, the limited number of orbital positions for new satellites has spurred an increase in payload data-communication capacity using an ever-increasing number of complex, multibeam active antennas and greater aggregate bandwidth. Only satellites with very large capacity, high computational density, and flexible, transparent, fully digital payload solutions can achieve affordable communication. To keep pace with these requirements, communicationsatellite designers must devise new systems requiring a total digital throughput of a few terabytes per second (Tb/s), resulting in a high-power-consuming satellite payload. An estimated 90% of the total power consumption per chip is used for off-chip communication. These factors taken together cause signal distortions in high-speed electrical data communication. For this reason, the European Space Agency commissioned us and others to carry out a literature study of interchip optical communications Figure 1. Growth in number of papers on board-level interconnects.