Roadmap to wide band optical GEO relay networks

Optical inter-satellite communication has been verified in-orbit. Between two LEO satellites bit error rates better than 10^-11 at a data rate of 5.625 Gbps are achieved. Optical LEO-to-ground and ground-to-LEO links have been demonstrated. For the first time ESA will apply optical communication for operational services. The LEO-to-GEO link of a GEO relay, EDRS, the European data relay system, shall be established by optical communication at a data rate of 1.8 Gbps with a bit error rate of 10^-8. For the time being the GEO-to-ground link still is based on radio frequency communication limiting the overall GEO relay data rate to the value of about 2 Gbps. Significantly higher data rates will be achieved by optical space-to-ground links with ground stations equipped with adaptive optics as has been demonstrated in a free-field measurement campaign. Optical LEO-to-ground and GEO-to-ground links shall be verified in the near future. Optical Air-to-GEO links are under preparation.