An underwater round-trip continuous variable quantum key distribution system and method thereof

Abstract

The invention discloses an underwater reciprocating continuous variable quantum key distribution system and method, comprising a light source sending end, a quantum signal encoding end, and a quantum signal receiving end. The light source sending end is used to generate the original signal light and the local oscillator light, and the local oscillator light is left at the light source sending end, and the original signal light is sent to the quantum signal encoding end through the forward water channel; the quantum signal encoding end is used to receive The original signal light, and encode the quantum information on the phase component of the original signal light light field, and then send the signal light loaded with quantum information to the quantum signal receiving end through the reverse water channel; the quantum signal receiving end, and the light source sending end A common port is used to detect the received quantum signal light with reference to the local oscillator light left at the sending end of the light source, and the detection result is fed back to the quantum signal encoding end through the forward water channel. The invention prevents the local oscillator from being attacked, ensures that polarization drift can be automatically compensated in the communication process, and improves system stability.

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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