Experimental study of secure quantum key distribution with source and detection imperfections

TL;DR

This paper presents an experimental decoy-state BB84 quantum key distribution system that accounts for source and detection imperfections, achieving secure key generation over 75 km fiber links and advancing practical QKD security.

Contribution

It provides a systematic security analysis considering multiple device imperfections and extends the theory to other discrete-variable QKD systems.

Findings

Achieved finite-key security over 75 km fiber links.

Considered more device imperfections than previous studies.

Extended security theory to other discrete-variable QKD systems.

Abstract

The quantum key distribution (QKD), guaranteed by the principle of quantum physics, is a promising solution for future secure information and communication technology. However, device imperfections compromise the security of real-life QKD systems, restricting the wide deployment of QKD. This study reports a decoy-state BB84 QKD experiment that considers both source and detection imperfections. In particular, we achieved a rigorous finite-key security bound over fiber links of up to 75 km by applying a systematic performance analysis. Furthermore, our study considers more device imperfections than most previous experiments, and the proposed theory can be extended to other discrete-variable QKD systems. These features constitute a crucial step toward securing QKD with imperfect practical devices.