Feasibility of satellite-to-ground continuous-variable quantum key distribution

Establishing secure communication links at a global scale is major potential application of quantum information science but also extremely challenging for the underlying technology. While milestone experiments using satellite-to-ground and exploiting singe-photon encoding implementing key distribution have shown recently that this goal achievable, it still necessary to further investigate practical solutions compatible with classical optical systems. Here we examine feasibility establishing secret keys in downlink configuration continuous-variable encoding, which can be implemented standard telecommunication components certified space environment able operate high symbol rates. Considering realistic channel model state-of-the-art technology, an orbit subdivision technique mitigating fluctuations transmission efficiency, find positive rates low-Earth-orbit scenario, while finite-size effects limiting factor higher orbits. Our analysis determines regions values important experimental parameters where exchange possible used as guideline efforts direction.