A Polarized Pairwise Encoding Method for Free-Space Continuous Variable Quantum Key Distribution

Abstract

The invention discloses a polarization pair encoding method for free space continuous variable quantum key distribution. The two polarized beams are modulated by I / Q, and after the polarization pair coding is completed, they pass through the polarization beam combiner, and then the signal is transmitted; after the signal is received: the polarization multiplexed signal is processed by the second polarization beam splitter. Demultiplexing to obtain two beams of polarized beams; then combined with the two beams of local oscillation signals obtained by the local oscillator through the beam splitter, the coherent detection is completed by the photodetector, and the two beams of polarized beams are measured; It is decoded in pairs to obtain the signal transmitted by the sender. The invention solves the problem that the polarization-related loss in the prior art will accumulate, resulting in increased signal distortion and greater error, thereby limiting the key distribution rate and transmission distance in the system.

Description

technical field [0001] The invention belongs to the technical field of continuous variable quantum key distribution, and relates to a polarization pairwise encoding method for free space continuous variable quantum key distribution. Background technique [0002] In the Internet era, with the rapid development of information science, how to improve the confidentiality and security of data 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 systems are 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 information security system based on mathematical problems will face difficult challenges in the near future, so new and eff...

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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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