Passive state preparation continuous variable quantum key distribution in a satellite-mediated link

Abstract

Passive state preparation (PSP) continuous variable quantum key distribution (CVQKD) drops out optical amplitude and phase modulators, making this scheme suitable for application in space-confined situations. In this paper, we propose a satellite-mediated PSP-CVQKD scheme. To improve the performance of the scheme further, we introduce a phase-insensitive amplifier (PIA) at the receiver side. Based on the detailed noise model and channel parameter estimation analysis, we perform numerical simulations of the proposed scheme while the finite-size effect is considered. Simulation results show that the satellite-mediated PSP-CVQKD is feasible in both downlink and uplink cases based on typical system parameters. The performance can be improved at a relatively low satellite altitude when the PIA is used. Our analysis demonstrates that the proposed scheme may be a potentially cost-effective solution for future chip-scale CVQKD over satellite-mediated links.