Passive light source monitoring method suitable for twin-field protocol

Abstract

The invention discloses a passive light source monitoring method suitable for a twin-field protocol. The method comprises the following steps: acquiring signal light and idle light obtained by splitting a light pulse subjected to intensity modulation; dividing the idle light into two light beams, detecting the two light beams, and obtaining four different counting events according to a detection result; estimating the parameters of the signal light through four different counting events so as to obtain a safe coding rate under a untrusted light source. Parameters of devices in a light source monitoring module do not need to be adjusted, the experiment difficulty is reduced, and safety reduction caused by modulation errors is avoided. The method is introduced by taking a twin-field quantum key distribution protocol as an example, is not only limited to be applied to a quantum key distribution process of the twin-field protocol, but also is suitable for quantum key distribution and quantum communication processes involving an untrusted light source, such as a BB84 protocol and a measurement equipment irrelevant protocol.

Description

technical field [0001] The invention relates to the technical field of a quantum key distribution system transmission system of an untrustworthy light source, in particular to a passive light source monitoring method suitable for a double-field quantum key distribution protocol. Background technique [0002] Over the years, Quantum Key Distribution (Quantum Key Distribution, QKD) has developed step by step in the game of attack methods and attack prevention schemes, but whether it is the original BB84 protocol or the later measurement device-independent In the Device Independent QKD (MDI-QKD) protocol, the coding rate is always limited by the transmission efficiency of the channel, resulting in a linear relationship between the transmission distance and the transmission efficiency. In 2018, the twin-field quantum key distribution (Twin-Field QKD, TF-QKD) proposed by Lucamarini et al. finally broke this boundary, and the TF-QKD protocol does not require the use of quantum rep...

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Problems solved by technology

[0003] Although both the MDI-QKD and TF-QKD protocols can be immune to the potential safety hazards of the QKD system at the detection end, in most existing QKD protocols, it is generally assumed that the light source at the transmitting end is credible, that is, the number of photons of the light source at the sending end The distribution is deterministic and known

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