Phase-encoded measurement device independent quantum key distribution with practical spontaneous parametric-down-conversion sources

TL;DR

This paper investigates phase-encoded measurement-device-independent quantum key distribution (MDI-QKD) using practical spontaneous parametric-down-conversion sources, demonstrating improved performance over weak coherent sources through numerical simulations.

Contribution

It provides a comprehensive analysis of MDI-QKD with SPDCS considering realistic parameters and compares active and passive decoy protocols, highlighting their performance advantages.

Findings

MDI-QKD with SPDCS can achieve comparable performance to idealized infinite decoy states.

Using thermal distributed SPDCS with active decoy protocol extends transmission distance and key rate.

Active three-intensity decoy protocol outperforms passive one-intensity protocol in practical settings.

Abstract

Measurement-device-independent quantum key distribution (MDI-QKD) with weak coherent sources has been widely and meticulously analyzed. However, the analysis for MDI-QKD with spontaneous parametric-down-conversion sources (SPDCS) is incomplete. In this paper, by accounting for practical parameters of SPDCS with thermal distribution, we presents an investigation on the performances of MDI-QKD under the active three-intensity decoy protocol and the passive one-intensity decoy protocol respectively. Phase randomization, inherently prerequisite for decoy protocol, is taken into consideration for evaluating the overall quantum bit gain and quantum bit error rate. The numerical simulations show that MDI-QKD using SPDCS with practical decoy protocols can be demonstrated comparable to the asymptotical case with infinite decoy states and has apparent superiority both in transmission distance and key generation rate compared to the MDI-QKD using weak coherent sources. Our results also indicate that MDI-QKD using thermal distributed SPDCS with active three-intensity decoy protocol performs better than the one with passive one-intensity decoy protocol.