A simple implementation of quantum key distribution based on single-photon Bell state measurement

TL;DR

This paper introduces a simplified implementation of single-photon Bell state measurement-based quantum key distribution, connecting it to traditional protocols and demonstrating its feasibility experimentally.

Contribution

The paper presents a straightforward SBSM-based QKD scheme built on existing BB84 setups, revealing its relation to phase-coding protocols and experimentally validating its practicality.

Findings

Simplified SBSM-based QKD implementation compatible with BB84 systems

Revealed the connection between SBSM-based and phase-coding QKD protocols

Experimental demonstration confirms feasibility of the proposed scheme

Abstract

Recently some alternatives of the measurement device independent quantum key distribution(MDI-QKD) based on the single-photon Bell state measurement (SBSM) have been proposed. Although these alternatives are not precisely as secure as MDI-QKD, they possess the advantage of high key rate of traditional BB84-like protocol and avoid the technical complexity of two-photon interference required in the MDI-QKD. However, the setups of these proposed schemes are rather complicated compared to commonly used BB84 systems. Here we propose a simple implementation of SBSM-based QKD which is directly built on the existing realization of BB84 QKD. Our proposal exhibits the hidden connection between SBSM-based QKD and traditional phase-coding QKD protocols. This finding discloses the physics behind these two different types of QKD protocols. In addition, we experimentally demonstrate the feasibility of our protocol.