LEO Satellites Constellation-to-Ground QKD Links: Greek Quantum Communication Infrastructure Paradigm

Quantum key distribution (QKD) has gained a lot of attention over the past few years, but the implementation of quantum security applications is still challenging to accomplish with the current technology. Towards a global-scale quantum-secured network, satellite communications seem to be a promising candidate to successfully support the quantum communication infrastructure (QCI) by delivering quantum keys to optical ground terminals. In this research, we examined the feasibility of satellite-to-ground QKD under daylight and nighttime conditions using the decoy-state BB84 QKD protocol. We evaluated its performance on a hypothetical constellation with 10 satellites in sun-synchronous Low Earth Orbit (LEO) that are assumed to communicate over a period of one year with three optical ground stations (OGSs) located in Greece. By taking into account the atmospheric effects of turbulence as well as the background solar radiance, we showed that positive normalized secure key rates (SKRs) up to 3.9×10−4 (bps/pulse) can be obtained, which implies that satellite-to-ground QKD can be feasible for various conditions, under realistic assumptions in an existing infrastructure