Phase‑matching quantum key distribution protocol based on passive light source monitoring

doi:10.3969/j.issn.1007-5461.2026.03.010

Abstract

Abstract: A phase-matching quantum key distribution (PM-QKD) protocol based on passive light source monitoring (PLSM) is proposed in this work. In this protocol, the response results of local detectors in the PLSM module are used to estimate the probability distribution of the light source, thereby avoiding the security issues introduced by the active light source monitoring (ALSM) scheme. Simulation results show that, when non-ideal light sources and modulation errors are taken into account, the performance of the proposed PLSM-PM-QKD protocol is significantly better than that of the ALSM-PM-QKD protocol. In other scenarios, the key rate and maximum transmission distance of the PLSM-PM-QKD protocol are nearly identical to those of the ALSM-PM-QKD protocol, and both of them are extremely close to those of the standard PM-QKD protocol. Additionally, the impact of the asymmetric channels and finite-length effects of the proposed protocal on the key rate performance is also analyzed.

Key words: quantum optics, phase-matching quantum key distribution protocol, non-ideal light source, passive light source monitoring

CLC Number:

O431.2

LÜ Bang , WANG Yilei , ZHU Xueyang , WANG Yifeng , FENG Bao . Phase‑matching quantum key distribution protocol based on passive light source monitoring[J]. Chinese Journal of Quantum Electronics, 2026, 43(3): 431-442.

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