Underwater reciprocating type continuous variable quantum key distribution system and method thereof

Abstract

The invention discloses an underwater reciprocating continuous variable quantum key distribution system and method. The system comprises a light source sending end, a quantum signal coding end and a quantum signal receiving end. The light source sending end is used for generating original signal light and local oscillation light, leaving the local oscillation light at the light source sending end,and sending the original signal light to the quantum signal coding end through a forward water channel; the quantum signal encoding end is used for receiving the original signal light, encoding quantum information on a phase component of an original signal light field, and then sending the signal light loaded with the quantum information to the quantum signal receiving end through a reverse waterchannel; and the quantum signal receiving end shares one port with the light source sending end, detects the received quantum signal light by taking the local oscillation light remained at the lightsource sending end as a reference, and feeds back a detection result to the quantum signal coding end through a forward water channel. According to the invention, local oscillation light is preventedfrom being attacked, polarization drift can be automatically compensated in the communication process, and the system stability is improved.

Description

technical field [0001] The invention belongs to the technical field of water channel quantum communication, and relates to an underwater round-trip continuous variable quantum key distribution system and a method thereof. Background technique [0002] Continuous variable quantum key distribution is a cutting-edge technology in the field of quantum encryption. It avoids the risk of eavesdropping on classical communication technology to a certain extent, and lays a theoretical and experimental foundation for the establishment of an unconditionally secure quantum communication network. Up to now, the unconditionally secure continuous variable quantum key distribution protocol has been applied in optical fiber and free space atmospheric channel, but the continuous variable quantum key distribution technology based on water channel is not mature. The ocean occupies more than 70% of the earth's area. Improving the underdeveloped underwater quantum communication is an inevitable pa...

AI Technical Summary

Problems solved by technology

Same as Gaussian modulation, in the process of discretely modulated underwater continuous variable quantum key distribution, in addition to quantum signal light, there is also classical local oscillator light transmitted on the channel, which is used as reference light for quantum state detection , and the local oscillator is vulnerable to third-party attacks when it is transmitted on the seawater channel, which reduces the security of the system. Therefore, how to avoid eavesdroppers' attacks on the local oscillator is particularly important

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