Obtaining better performance in the measurement-device-independent quantum key distribution with heralded single-photon sources

Measurement-device-independent quantum key distribution (MDI-QKD) has been widely investigated due to its remarkable advantages on the achievable transmission distance and practical security. However, the relative low key generation rate limits its real-life implementations. In this work, we adopt the newly proposed four-intensity decoy-state scheme [Phys. Rev. A 93, 042324 (2016)] to study the performance of MDI-QKD with heralded single-photon sources (HSPS). Corresponding simulation results demonstrate that the four-intensity decoy-state scheme combining HSPS can drastically improve both the key generation rate and transmission distance in MDI-QKD, which may be very promising in future MDI-QKD systems.

Figure 1

(a) Comparison of the key generation rate (take the logarithm of 10) between WCS (green dashed line) and HSPS (red solid line) all using the new four-intensity method. The data size is $N={10}^{10}$. (b) The relative key generation rate: HSPS to WCS.

Figure 2

Comparison of the key generation rates (take the logarithm of 10) using different protocols. The two dashed (dotted) lines from left to right denote the results of the three-intensity method by Xu et al. and the new four-intensity method with $N={10}^{11}$ ($N={10}^{10}$) pulses using HSPS.