System and method for reducing QKD (quantum key distribution) system bit error rate based on extended Kalman filter

Abstract

The invention provides a system and method for reducing QKD (quantum key distribution) system bit error rate based on extended Kalman filter. A phase drift parameter value is obtained in real time by an extended Kalman filter algorithm, the final voltage difference is sent to the phase modulator at a receiving terminal by using the relation of phase and voltage, therefore phase change of the phase modulator is controlled, real time active phase compensation is realized. According to the system and method for reducing QKD (quantum key distribution) system bit error rate based on extended Kalman filter, the operation quantity and operation time of obtaining the phase shift parameters are reduced, the convergence speed of a phase shift parameter curve is accelerated, the phase shift parameters are obtained in real time; the convergence speed is high; the efficiency is high; the stability of the QKD system is improved; the bit error rate is reduced; the phase shift parameters are obtained only by a mathematical method without adding hardware and software arrangement; the calculation quantity is little; and the long distance transmission of the QKD system is realized.

Description

technical field [0001] The present invention relates to the technical field of quantum communication, in particular to a method and system for reducing the bit error rate of a quantum key distribution (QuantumKeyDistribution, QKD) system based on extended Kalman filtering. Background technique [0002] Quantum communication is based on quantum physics and cryptography, combined with basic characteristics such as Heisenberg’s uncertainty principle and no-cloning theorem. A new way of thinking has become an emerging communication technology. As for the bit error problem of quantum communication, there are two main sources: one is caused by the eavesdropper's eavesdropping behavior; the other is the bit error caused by the instability of the system, which belongs to the problem of quantum key distribution technology. [0003] The existing technical solutions for solving the bit error rate mainly include the following two types: [0004] (1) First, in the stage of active phase...

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Problems solved by technology

[0008] However, in the above-mentioned existing solution to the phase drift of the QKD system, if the collected data points are not enough, it will not be convincing, and will generate a greater bit error rate; A set of data needs to be calculated every time before the phase drift value can be obtained, which leads to a long time to obtain the phase drift result and poor real-time performance. The result cannot be fed back to the system in real time, which increases the error of the system.

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