Eurasian-Scale Experimental Satellite-based Quantum Key Distribution with Detector Efficiency Mismatch Analysis

TL;DR

This paper reports on satellite-based quantum key distribution experiments using the Micius satellite, analyzing security with detector efficiency mismatch, and validating a semi-empirical model for realistic receiver conditions.

Contribution

It extends security analysis of satellite QKD by incorporating detector efficiency mismatch and validates a semi-empirical model against experimental data.

Findings

Successful satellite QKD with 2.5 Mbit sifted key

Extended security analysis considering detector mismatch

Model validation shows good agreement with experiments

Abstract

The Micius satellite is the pioneering initiative to demonstrate quantum teleportation, entanglement distribution, quantum key distribution (QKD), and quantum-secured communications experiments at the global scale. In this work, we report on the results of the 600-mm-aperture ground station design which has enabled the establishment of a quantum-secured link between the Zvenigorod and Nanshan ground stations using the Micius satellite. As a result of a quantum communications session, an overall sifted key of 2.5 Mbits and a total final key length of 310 kbits have been obtained. We present an extension of the security analysis of the realization of satellite-based QKD decoy-state protocol by taking into account the effect of the detection-efficiency mismatch for four detectors. We also simulate the QKD protocol for the satellite passage and by that validate our semi-empirical model for a realistic receiver, which is in good agreement with the experimental data. Our results pave the way to the considerations of realistic imperfection of the QKD systems, which are important in the context of their practical security.