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SUMMARY Optical backhaul downlinks from high-altitude platforms (HAPs) are investigated. An experiment demonstrated the advantages of optical links: a small and lightweight terminal with low power consumption was launched to the stratosphere and data transmitted down to a ground station at a rate of 1:25 Gbit=s: Owing to the chosen system parameters and the(More)
Between a high-altitude platform (HAP) in the stratosphere and a satellite, high-data-rate optical links are conceivable but the challenges are still not clearly identified. We thus review the main requirements to properly establish such links. The design of a HAP-LEO link is in several aspects different from that of a HAP-GEO link. Among others, we(More)
Telecommunication satellites must follow the advances of terrestrial network capacities and increase their total throughputs in order to remain competitive. This paper shows how the terrestrial fibre technology at 1550-nm wavelength can be extended to support an optical feeder link between ground and a GEO satellite. With 100 Gb/s in a single direction, an(More)
The impact of clouds on optical Earth-space links is assessed by means of theoretical analyses. The spacecraft is assumed geostationary so that a stationary model can be considered for the link availability. Binary and continuous attenuations are analysed separately. With a network of ground stations, both spatial diversity and multiplexing are considered.(More)
Optical data links through the atmosphere suffer from turbulence-induced signal scintillation. In a coaxially-symmetric bidirectional link scenario, the variations of the axial intensities at both ends are correlated. This relation can be used as an inherent feedback mechanism, with negligible delay, to enhance the capacity of the transmission system. By(More)
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