A Long-Distance Continuous Variable Quantum Key Distribution Method Based on Gaussian Modulated Coherent States

Abstract

The present invention provides a long-distance continuous variable quantum key distribution method based on Gaussian modulation coherent state, including: Step A: The continuous variable initial key distribution step refers to using the sender Alice to perform Gaussian modulation through the coherent state and pass through the optical fiber After the long-distance transmission of the channel, the receiving party Bob performs demodulation and detection to obtain the initial continuous key data; Step B: refers to using the data post-processing algorithm to preprocess, error correct and enhance the security of the initial continuous key data obtained, Get the ultimate secure binary bit key. The invention can extend the safe communication distance of the CVQKD system based on Gaussian modulation coherent state to 100-150km.

Description

technical field [0001] The present invention relates to quantum key distribution, in particular, to a long-distance continuous variable quantum key distribution method based on Gaussian modulation coherent state, especially a method for optimizing the over-noise control, homodyne detection and data post-processing of the CVQKD system Technology for long-distance CVQKD communication. Background technique [0002] Since the academic community first proposed the use of continuous variables for quantum communication in 1999, many scholars at home and abroad have proposed many continuous variable quantum secure communication protocols, especially CVQKD (continuous variable quantum key distribution) has attracted great attention. CVQKD allows two communicating parties, Alice and Bob, to obtain keys through quantum channels and authenticated classical channels. Unlike DVQKD (Discrete Variable Quantum Key Distribution), in the CVQKD protocol, Alice uses Gaussian modulation to modul...

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Problems solved by technology

The CVQKD experimental system with an optical fiber transmission distance of more than 100km has not been reported in the world so far. The basic bottleneck lies in two aspects. One is the noise suppression of coherent optical signals by the optical path codec module in the initial key distribution stage and the detection of extremely weak signals. ; The other is the efficient negotiation of the initial key in the data post-processing stage

The former is because the long distance will introduce more noise, including the leakage of strong local oscillator light, polarization and phase drift, and the signal light will be weakened to be difficult to detect after long-distance transmission; the latter is the signal noise under long-distance transmission. The ratio will be extremely low, and efficient negotiation under extremely low SNR is a difficult problem

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