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Research funding: Canadian Space Agency, Canadian Institute for Advanced Research, Industry Canada, and the Natural Sciences and Engineering Research Council (NSERC).Ĭonflict of interest statement: The authors declare no conflicts of interest regarding this article. acknowledges support from NSERC Banting Postdoctoral Fellowships.Īuthor contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission. thanks NSERC and the province of Ontario for funding. AO coupled with a laser guide star would thus deliver a significant increase in the secret key generation rate of the QKD ground-to-space uplink system, especially as reductions of channel loss have a favourably nonlinear key-rate response within this high-loss regime.Ĭ.J.P. Examining both low Earth orbit and geostationary uplink scenarios, we find that a modest link transmissivity improvement of about 3 dB can be obtained in the case of a coaligned downward beacon, while the link can be dramatically improved, up to 7 dB, using an offset beacon, such as a laser guide star. Here, we model the effect of the atmosphere on link efficiency between an Earth station and a satellite using an optical uplink and how AO can help recover from loss due to turbulence. Adaptive optics (AO) techniques have been used in astronomical, communication, and other applications to reduce the detrimental effects of turbulence for many years, but their applicability to quantum protocols, and their requirements specifically in the uplink scenario, is not well established. The performance of applied protocols such as quantum key distribution (QKD) depends significantly on the transmission efficiency through the turbulent atmosphere, which is especially challenging for ground-to-satellite uplink scenarios. For quantum communications, the use of Earth-orbiting satellites to extend distances has gained significant attention in recent years, exemplified in particular by the launch of the Micius satellite in 2016.

Uplink mod state of decay 2