Addition and subtraction photonic system for improving continuous variable quantum key distribution under water and its implementation method

Abstract

The invention discloses a photon increasing and decreasing system for improving underwater continuous variable quantum key distribution and an implementation method thereof. In the system, a dual-modecompression state is prepared in advance by using a laser, a signal source and a modulator at a transmitting end, heterodyne detection is performed on a half quantum state after the dual-mode compression state passes through a beam splitter, photon increasing operation is performed on the other half quantum state firstly, then photon decreasing operation is performed, and the quantum state afteroperation is transmitted to a receiving end through a water channel. And the receiving end demodulates the received quantum state, performs homodyne detection on the demodulated quantum state, and finally establishes a security key within an effective distance. According to the invention, the underwater continuous variable quantum key distribution technology is improved, the used quantum signal isnot easily eavesdropped by a third party, and the underwater communication security is ensured. Homodyne detection is used for filtering external interference light, a good detection effect can be achieved under the condition that external light interference exists, the effective distance of underwater continuous variable quantum key distribution is prolonged, and more practicability is brought to underwater quantum communication.

Description

technical field [0001] The present invention relates to the technical field of quantum key distribution, in particular to a method for long-distance continuous variable quantum key distribution based on non-Gaussian modulation coherent state, especially to optimize the performance of underwater continuous variable quantum key distribution after adding and subtracting photon operations, To realize the increase and decrease photonic system and its implementation method for improving the underwater continuous variable quantum key distribution. Background technique [0002] Quantum communication is a new type of communication method, and quantum key distribution is a very important part of it. Underwater communication is crucial in modern communication because it involves information interaction between various underwater devices. The traditional way of underwater communication is to use underwater acoustic technology, which has obvious disadvantages, such as low scalability, l...

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Problems solved by technology

[0004] In order to achieve the above-mentioned purpose, the present invention provides a kind of increase and decrease photon system that improves the underwater continuous variable quantum key distribution, which solves the problems of low performance and short effective distance of underwater continuous variable quantum key distribution existing in the prior art. question

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