Performance optimization for quantum key distribution in lossy channel using entangled photons

Abstract

In quantum key distribution (QKD), the times of arrival of single photons are important for the keys extraction and time synchronization. The time-of-arrival (TOA) accuracy can affect the quantum bit error rate (QBER) and the final key rate. To achieve a higher accuracy and a better QKD performance, different from designing more complicated hardware circuits, we present a scheme that uses the mean TOA of M frequency-entangled photons to replace the TOA of a single photon. Moreover, to address the problem that the entanglement property is usually sensitive to the photon loss in practice, we further propose two schemes, which adopt partially entangled photons and grouping-entangled photons, respectively. In addition, we compare the effects of these three alternative schemes on the QKD performance and discuss the selection strategy for the optimal scheme in detail. The simulation results show that the proposed schemes can improve the QKD performance compared to the conventional single-photon scheme obviously, which demonstrate the effectiveness of the proposed schemes.

Finite-size analysis of eight-state continuous-variable quantum key distribution with the linear optics cloning machine

“…Based on the security analysis above, the performance of LOCM in our scheme mainly depends on two parameters τ and λ . In our simulation, the fluctuation of the value of excess noise ε [40,41] exerts a small influence on the final value of secret key rate K f , thus we set ε to be a conservative value ε = 0.005. More details of parameter settings are shown in Table 1.…”