Polarization paired coding method for free space continuous variable quantum key distribution

Abstract

The invention discloses a polarization paired coding method for free space continuous variable quantum key distribution, which sequentially comprises the following steps: a sender and a laser generating laser pulses, an amplitude modulator adjusting signals, and the laser pulses being decomposed into two orthogonal polarized beams through a first polarization beam splitter; the two polarized lightbeams being subjected to I / Q modulation, after polarization paired coding is completed, performing signal transmission through a polarization beam combiner; after the signal is received, demultiplexing the polarization multiplexing signal through a second polarization beam splitter to obtain two polarized beams; combining two beams of local oscillation signals obtained by a local oscillator through a beam splitter, completing coherent detection through a photoelectric detector, and measuring two beams of polarized light beams; and performing polarization paired decoding by the polarization paired decoding module to obtain a signal transmitted by the sender. According to the invention, the problems in the prior art that the polarization dependent loss is accumulated, the signal distortionis increased, larger errors are generated, and the key distribution rate and the transmission distance in the system are limited are solved.

Description

technical field [0001] The invention belongs to the technical field of continuous variable quantum key distribution, and relates to a polarization pair coding method for free space continuous variable quantum key distribution. Background technique [0002] In the Internet age, with the rapid development of information science, how to improve data confidentiality and security has always been a key concern of users. Therefore, information security, an important scientific exploration topic, has epochal significance for modern development. The currently widely used cryptographic system is based on mathematical problems that have not been perfectly calculated. However, with the development of technology, the computing power of current computers is constantly breaking through, and the first quantum computer has come out. This means that this kind of information security system based on mathematical problems will face difficult challenges in the near future, so it is necessary to...

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Problems solved by technology

[0005] In order to achieve the above-mentioned purpose, the present invention provides a polarization pairwise encoding method for free-space continuous variable quantum key distribution, which solves the problem of accumulation of polarization-dependent losses in the prior art, resulting in increased signal distortion and larger errors. Thus limiting the key distribution rate and transmission distance in the system

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