Method and device for preparing high-speed polarization encoded decoy state quantum light source

Abstract

The invention discloses a method and a device for preparing a high-speed polarization encoding decoy state quantum light source. The device comprises a high-speed logic control chip, a decoy state light pulse driving module, a high-speed phase modulator driving module, a laser diode, a high-speed phase modulation polarization rotating module and an optical attenuator, wherein the decoy state light pulse driving module receives a control signal from the high-speed logic control chip, randomly modulates according to the proportion requirement of a decoy state quantum light source implementation scheme to generate a decoy state electric pulse signal of three impulse amplitudes and drives the laser diode to output decoy state light pulse of three light intensities; the decoy state light pulse signal passes through the high-speed phase modulation polarization rotating module, is randomly modulated to be in four polarization states such as linear polarization-based state and circular polarization-based state through the high-speed phase modulator and is attenuated to be in a single photon level through the optical attenuator. According to the device and the method, any one state in totally nine quantum states comprising three average photon number intensities and four polarization states can be generated through high-rate random modulation, the device is small in size, compact in structure and easy to integrate, and the safety level is effectively improved.

Description

technical field [0001] The invention belongs to the category of quantum key distribution, and in particular relates to the preparation of a decoy quantum state suitable for a high-speed polarization coding quantum key distribution (QKD) system, that is, a preparation method and device for a high-speed polarization coding decoy state quantum light source. Background technique [0002] Quantum cryptography originated from the "BB84 protocol" proposed by Bennett and Brassard in 1984. Compared with traditional encryption methods based on algorithm complexity, the security of Quantum Key Distribution (QKD) is determined by the basic principles of physics. Guaranteed, and therefore an absolutely secure means of communication that cannot be cracked. The existing mainstream QKD system mainly consists of the following three schemes: the QKD scheme based on "plug & play" phase encoding, the QKD scheme based on polarization encoding, and the QKD scheme based on entangled photon pairs. ...

AI Technical Summary

Problems solved by technology

Combined with the decoy state scheme, the system needs a total of eight laser diodes, which undoubtedly increases the complexity of the system, reduces the compactness of the system, and is not conducive to the engineering integration of the QKD system

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