Two-dimensional distributed-phase-reference protocol for quantum key distribution

TL;DR

This paper introduces a novel two-dimensional distributed-phase-reference quantum key distribution protocol that encodes information in time and phase, enhancing secret key rates while maintaining practicality and integrability.

Contribution

It presents the first 2D DPR-QKD protocol, increasing information capacity per detection and improving performance in realistic quantum communication networks.

Findings

Enables extraction of two bits per detection event.

Maintains simplicity and practicality despite added dimensions.

Potential for higher secret key rates in fiber-based QKD.

Abstract

Quantum key distribution (QKD) and quantum communication enable the secure exchange of information between remote parties. Currently, the distributed-phase-reference (DPR) protocols, which are based on weak coherent pulses, are among the most practical solutions for long-range QKD. During the last 10 years, long-distance fiber-based DPR systems have been successfully demonstrated, although fundamental obstacles such as intrinsic channel losses limit their performance. Here, we introduce the first two-dimensional DPR-QKD protocol in which information is encoded in the time and phase of weak coherent pulses. The ability of extracting two bits of information per detection event, enables a higher secret key rate in specific realistic network scenarios. Moreover, despite the use of more dimensions, the proposed protocol remains simple, practical, and fully integrable.