Underwater continuous variable quantum key distribution system and its implementation method for complex environments

Abstract

The invention discloses a complex environment-oriented underwater continuous variable quantum key distribution system and its implementation method. The system includes a signal sending end, a seawater transmission channel and a signal receiving end, and the signal sending end performs discrete modulation and loading on pulses. After the key information is sent to the signal receiving end through the seawater transmission channel, the signal receiving end uses a hybrid linear amplifier to amplify the quantum signal, and then performs coherent detection to obtain the key information; the invention can improve the quantum The key rate of key distribution can extend the transmission distance and reduce the risk of key loss.

Description

technical field [0001] The invention belongs to the technical field of quantum communication, in particular to a complex environment-oriented underwater continuous variable quantum key distribution system and an implementation method thereof. Background technique [0002] As a part of the global communication system, the underwater communication system plays a vital role in many fields such as seabed exploration and marine military. The defect of being eavesdropped, compared with the traditional communication technology, the continuous variable quantum key distribution (CV-QKD) technology can avoid the risk of being eavesdropped to a certain extent, and has been greatly developed in recent years; The technology has been experimentally verified in optical fiber communication systems and free space atmospheric communication systems, and has been proven to have good commercial application prospects. However, the application of this technology in underwater communication systems...

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Problems solved by technology

[0002] As a part of the global communication system, the underwater communication system plays a vital role in many fields such as seabed detection and marine military affairs. Traditional underwater communication usually uses sound wave technology, but there are problems in the use of this technology. The defect of being eavesdropped, compared with the traditional communication technology, the continuous variable quantum key distribution (CV-QKD) technology has been greatly developed in recent years because it can avoid the risk of being eavesdropped to a certain extent; so far, the The technology has been experimentally verified in the optical fiber communication system and the free space atmospheric communication system, and it has been proved to have good commercial application prospects. However, the application of this technology in the underwater communication system has been delayed, which is mainly due to Due to the strong attenuation effect caused by the absorption and scattering of light by the water medium, the transmittance of the signal light in water is low, which leads to a low key generation rate and a short safe key transmission distance. In complex situations such as obstacles in between, the signal light will not be able to transmit, resulting in communication failure

[0003] Since the absorption and scattering of light by the water medium is determined by its own composition, it is impossible to increase the transmittance of the system by changing the water quality in a specific scene to achieve the purpose of improving system performance. In addition, due to the CV-QKD The essence of technology is still optical communication technology, and the propagation of signal light may be blocked when facing complex underwater environments. In this case, how to improve the ability of the system to adapt to complex environments, and how to improve the key generation rate of the system, Prolonging the safe transmission distance of keys is related to the application prospect of CV-QKD technology in underwater communication systems

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