China News Agency Hefei, May 5 (Reporter Wu LAN) The reporter learned from the University of Science and Technology of China on the 5th that Pan Jianwei and Zhang Qiang of the school cooperated with Wang Xiangbin and Liu Yang of the Jinan Institute of Quantum Technology to greatly break through the limitation that the distance of traditional fiber optic vibration sensing technology is difficult to exceed 100 kilometers, and successfully realized 658 kilometers long distance fiber optic vibration sensing, and the positioning accuracy reached 1 kilometer.

The findings were published as an "editor's recommendation" in the journal Physical Review Letters.

Fiber optic vibration sensing uses fiber as a sensor for vibration sensing. Due to its advantages of high sensitivity, fast response, simple structure and uniform distribution, fiber optic vibration sensing has wide application prospects in structural health monitoring, oil and gas pipeline leakage monitoring, perimeter protection and earthquake monitoring. At present, fiber optic vibration sensing mostly uses distributed acoustic wave sensing technology, and its sensing distance is limited to 100 km. An important technical challenge is how to overcome the distance limitation and realize long-distance fiber optic vibration sensing.

Quantum key distribution (QKD) is based on the basic principles of quantum mechanics, combined with the "one time secret" encryption method, can achieve unconditional security of confidential communication. Because of its important practical significance, QKD has been the focus of international academic research in the past decades. The TF-QKD protocol, proposed in 2018, is considered to be the best scheme to achieve ultra-long distance fiber QKD. However, in practical applications, noise such as sound and vibration along optical fiber links is unavoidable.

In this study, the researchers integrated the experimental system of long-distance quantum key distribution and fiber optic vibration sensing, and completed the fiber optic two-field quantum key distribution (TF-QKD) at the same time, finally realized the 658 kilometers of fiber optic two-field quantum key distribution and fiber optic vibration sensing, and located the disturbance position of the artificial vibration source on the link, with an accuracy of better than 1 km.

The above research results show that TF-QKD network architecture can not only realize ultra-long distance distribution of security keys, but also be applied to ultra-long distance vibration sensing, and realize the fusion of wide-area quantum communication network and optical fiber sensing network. (over)

Source: China News (07/05/2022)

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