A polarization-encoded measurement device-independent quantum key distribution system

Abstract

The invention provides a quantum key distribution system irrelevant to polarization coding measurement equipment. Composed of beam splitting and combining modules, the Bell state measuring device includes beam splitter BS, circulator CIR, first polarizing beam splitter PBS1, second polarizing beam splitter PBS2 and 4 single photon detectors SPD, orthogonal polarization pulse splitter The bundle combination module has a first port, a second port, a third port and a fourth port. Compared with the prior art, the polarization-encoded measurement equipment-independent quantum key distribution system of the present invention only uses a single laser combined with a reciprocating structure, which can eliminate the problem of inconsistency between the frequencies of the two lasers, and at the same time automatically compensate for channel polarization changes to achieve polarization state The stable preparation and transmission without any active compensation module reduces the complexity of the system and improves the stability and practicability of the system.

Description

technical field [0001] The invention relates to the technical field of quantum polarization coding, in particular to a quantum key distribution system independent of polarization coding measurement equipment. Background technique [0002] The proposal of the measurement-device-independent quantum key distribution protocol (measurement-device-independent, MDI-QKD) removes the trustworthy requirements for the measurement end, can resist all attacks against the measurement end, and greatly improves the actual security of the system. [0003] In the MDI-QKD protocol, the legitimate communication parties Alice and Bob prepare quantum states respectively, and send them to the untrusted third party Charlie for Bell state measurement, which is equivalent to the time-reversal EPR quantum key distribution protocol. The core part of the Bell state measurement is the Hong-Ou-Mandel (HOM) interference, that is, the quantum states sent by Alice and Bob interfere at Charlie's beam splitter...

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Problems solved by technology

[0004] Conventional polarization-encoded MDI-QKD schemes inevitably require the use of polarization calibration modules when performing Bell state measurements, such as the document "Experimental demonstration of polarization encoding measurement-device-independent quantum key distribution." Phys. Rev. Lett.112 , 190503 (2014) and the document "Proof-of-principled demonstration of measurement-device-independent quantum key distribution based on intrinsically stable polarization-modulated units." Optics express 28.8 (2020): 10772-10782 adopted the scheme, Alice and Bob respectively Independent lasers are used to generate 4 stable polarization states, but the polarization states become random after passing through the fiber channel, requiring active polarization compensation, and there are problems with inconsistent wavelengths

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