Phase decoding method and device based on polarization orthogonal rotation, and quantum key distribution system

Abstract

The invention discloses a phase decoding method and device based on a polarization orthogonal rotation, and a quantum key distribution system. The method comprises the steps: splitting an input optical pulse in any polarization state into two optical pulses, transmitting the optical pulses along two optical paths, and combining the optical pulses for output, wherein at least one optical path comprises at least one polarization orthogonal rotating device, and the polarization orthogonal rotating device is configured to be used for the polarization orthogonal rotation of the two orthogonal polarization states of one optical pulse transmitted through the path, so that each polarization state of the one optical pulse is converted into a polarization state orthogonal thereto, and two positivesof the input optical pulse are controlled. The phase difference between one of the orthogonal polarization states of the input optical pulse transmitted by the two optical paths in the splitting-to-combining process and the phase difference of the other polarization state transmitted through the two optical paths are controlled, so that the difference between the two phase differences is an integer multiple of 2*pi. According to the invention, at least one of the two optical paths employs the polarization orthogonal rotating device, so the method enables the phase difference requirements of the stable decoding to be met more easily, thereby achieving the stable phase decoding resisting environment interference.

Description

technical field [0001] The invention relates to the technical field of optical transmission secure communication, in particular to a phase decoding method and device based on polarization orthogonal rotation, and a quantum key distribution system. Background technique [0002] Quantum secure communication technology is a frontier hot field combining quantum physics and information science. Based on the quantum key distribution technology and the principle of one-time pad cryptography, quantum secure communication can realize the secure transmission of information in open channels. Quantum key distribution is based on physical principles such as the Heisenberg uncertainty relation of quantum mechanics and the quantum non-cloning theorem. It can safely share keys between users and detect potential eavesdropping behaviors. It can be applied to national defense, government affairs, and finance. , electric power and other fields with high security information transmission requir...

AI Technical Summary

Problems solved by technology

However, when the phase encoding scheme is interferometrically decoded, due to the birefringence of the transmission fiber and the codec interferometer fiber, there is a problem of polarization-induced fading, resulting in unstable decoding interference.

Similarly, if the correction device is added, although only one polarization state needs to be corrected, it also increases the complexity and cost of the system

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