This project belongs to the field of information technology.
The security of the country's core areas and major infrastructure is the guarantee for the sustainable development of the country's economy and society, the maintenance of national security and political stability. As the development frontier of intrusion detection and perimeter security technology, distributed optical fiber vibration sensing technology overcomes the shortcoming that conventional optical fiber sensing technology is difficult to carry out all-round continuous monitoring of tested objects. It has irreplaceable advantages in sensing and detection distance, accurate event positioning, concealment, environment adaptability and other aspects, and is a strategic emerging industry that has been mainly developed at home and abroad in recent years. Starting from the actual security needs of accurately identifying intrusions and sabotage behaviors in complex environments, and with the support of the National Natural Science Foundation of China, the 863 Program and other projects, the project has gone through the invention of principles and methods, innovation of core technologies and devices, equipment development and integration, and development of engineering applications. At the stage, after years of unremitting efforts, a distributed optical fiber vibration sensing and security application technology system with independent intellectual property rights has been formed, solving many bottleneck problems that limit the practical application of this technology. It has gained important applications in the security field of national core areas and major infrastructure.
The main inventions and core key innovation technologies of this project mainly include:

1. A phase-sensitive optical time domain reflectometer method based on phase demodulation is proposed. Digital coherent detection technology is used to realize distributed phase measurement of weak Rayleigh scattering signals for the first time, breaking through the bottleneck that traditional technology cannot quantitatively measure external disturbance information;
2. Invented a laser noise characteristic testing method and a series of laser noise suppression technologies, solved the problem of high-precision measurement of the noise characteristics of high-performance sensing light sources, and developed an ultra-low-noise, ultra-narrow linewidth single-frequency laser, which improved the system's signal-to-noise ratio and sensing distance;
3. A complete technical system for distributed optical fiber vibration sensing based on phase demodulation and its security applications has been established, and innovative technologies such as coherent fading suppression and high-bandwidth measurement have been proposed, providing effective guarantees for the productization and competitiveness of the project technology;
4. A fast pattern recognition technology based on the spectral Euclidean distance method is proposed, and real-time processing software for distributed vibration sensor data is developed. Through the screening of time-domain signals and the extraction of frequency-domain and airspace features, rapid and accurate identification of intrusion signals is realized., laying the foundation for practical security applications in national core areas and major infrastructure.
   This project has obtained a total of 22 authorized invention patents, 1 software copyright, and 1 national public security industry standard. The results obtained in the field of optical fiber sensing technology have been highly recognized by international colleagues, and 67 papers have been published in well-known academic journals and conferences, including 10 specially invited reports; 2 academic monographs have been published, of which "Fundamentals of Optical Fiber Sensors" was published by WILEY Press, an internationally renowned academic publishing institution in the United States.
   The scientific and technological novelty search conclusion of the National Science and Technology Novelty Search Agency pointed out: "The overall technology of the project has reached the international advanced level, among which the quantitative detection technology of vibration signals based on phase demodulation and its actual security application technology rank internationally."
   The project results have been successfully industrialized and are superior to similar products at home and abroad in terms of key performance. They have obtained a number of national mandatory product certifications and have been applied to the safety monitoring of a number of major infrastructure projects, including West-East Gas Pipeline Oil and Gas Pipeline, power cables and submarine cables, and facilities along railways. A total of 117 million yuan in direct economic benefits have been achieved in the past three years. In addition, they have successfully entered the international market and generated more than US$3 million in foreign exchange. What is particularly important is that the project results have been successfully applied to security projects in core areas with the highest security requirements in my country, providing advanced and reliable technical means for security in core areas of the country, which is of great significance.
   This project has achieved major breakthroughs and innovations at the international leading level, and has played a leading role in the field of distributed optical fiber vibration sensing and its security applications, with significant social and economic benefits.