A new publication from Opto-Electronic Advances; DOI 10.29026/oea.2022.200078 overviews advances in distributed fiber optic vibration/acoustic sensing technology.
Distributed fiber optic vibration/acoustic sensing technology utilizes the Rayleigh back-scattered light generated by periodically injecting laser pulses into fiber under test (FUT) to achieve long-range, high spatial resolution vibration detection over the entire length of the FUT. Compared with traditional electrical or mechanical sensors, this technology operates in a fully distributed manner with high sensitivity, remote accessibility and immunity to electromagnetic interference, making it suitable for various application prospects, especially under extreme environmental conditions.
Phase-sensitive optical time-domain reflectometry (φ-OTDR) technology has been rapidly developing since the first fiber optic distributed vibration sensing (DVS) system based on φ-OTDR was introduced in 2005. It was later evolved into distributed acoustic sensing (DAS) technology with the ability to quantitatively analyze acoustic waveforms. On this basis, researchers have conducted extensive research to enhance the sensing performances of φ-OTDR systems, including key performance parameters such as sensing distance, spatial resolution, frequency response range, and event recognition accuracy. Based on its superior long-range and high-resolution distributed sensing capability, φ-OTDR has been widely used in engineering applications in recent years, especially in the emerging fields of seismic wave acquisition, oil and gas resource exploration, pipeline leakage detection, perimeter protection, cable partial discharge monitoring, etc.
In the future, with the development of sensitivity-enhanced fiber optic cable, novel sensing mechanism, efficient signal processing procedures, and accurate vibration event recognition algorithms, φ-OTDR-based DVS/DAS will show great potential for a broad range of commercial applications, including distributed fiber shape sensing and geological exploration. Finally, this article discussed the prospects and challenges of the future development of φ-OTDR-based DVS/DAS technology.
The research groups of Professor Liyang Shao from Southern University of Science and Technology, China and Professor Feng Wang from Nanjing University, China jointly reviewed the research progress of φ-OTDR-based fiber optic DVS/DAS technology and its emerging applications. Firstly, the sensing principles of DVS-φ-OTDR based on Rayleigh backscattered light intensity demodulation, and DAS-φ-OTDR system based on phase demodulation were analyzed. The DAS phase demodulation techniques, such as heterodyne detection scheme with I/Q demodulation, heterodyne detection scheme with Hilbert transform, direct detection scheme based on 3x3 coupler and direct detection scheme based on phase-generating carrier algorithm, were introduced and compared. Then, the performance enhancement methods were discussed and analyzed in detail for the key sensing parameters of φ-OTDR systems, including maximum sensing distance, signal-to-noise ratio, vibration frequency response range, spatial resolution, and accuracy of vibration pattern recognition.
This review further summarizes the engineering applications of φ-OTDR systems in various fields, involving geological exploration, pipeline protection, perimeter security, and cable partial discharge detection, as well as special applications such as shape sensing, gas concentration sensing, and pest infection detection.
Article reference: Liu SQ, Yu FH, Hong R, Xu WJ, Shao LY et al. Advances in phase-sensitive optical time-domain reflectometry. Opto-Electron Adv 5, 200078 (2022). doi: 10.29026/oea.2022.200078
Keywords: optical fiber sensors / Ф-OTDR / phase demodulation / application research
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Liyang Shao is the Deputy Dean of School of Innovation and Entrepreneurship, and tenured professor of the Department of Electrical and Electronic Engineering, Southern University of Science and Technology, China. He has authored more than 140 SCI papers with over 2200 citations and an H-index of 34, and holds 10 Chinese patents. He is a member of the technical or organizing committee of many international conferences, such as OFS, ACP, TPC and ICAIT, and has given over 40 conference presentations including over 10 invited talks at international conferences. He has presided over the International Cooperation Special Project of the Ministry of Science and Technology of China, National Natural Science Foundation of China (general/key projects), and several province level research projects, with funding totalling 20 million RMB. His research group is committed to conducting theoretical research in the fields of optical sensing and measurement technology, micro- and nano- optics, and nonlinear optics. His group seeks to apply optical information and sensing technology to the application of earthquake monitoring, rail transportation, perimeter security, infrastructure protection, biochemistry and life health.
Feng Wang is the Deputy Director of Optical Communication Engineering Research Center of Nanjing University, China. He serves as a senior member of Optica and Institute of Electrical and Electronics Engineers (IEEE), and member of the Optics Education Committee of the Chinese Optical Society. He has presided over and participated in 6 research projects from the National Natural Science Foundation of China, 2 projects of 973 program and National Key Research and Development Program, and 3 projects from Jiangsu Province. He has authored more than 80 SCI papers, applied for/granted more than 50 patents, won the first prize of the Technical Invention Award of the Ministry of Education, the first prize of Jiangsu Province Science and Technology Award, and the first prize of the 5th Wu Wen Jun AI Science & Technology Award. His research team focuses on distributed fiber optic sensing and fiber Bragg grating sensing technology and applications.
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Opto-Electronic Advances (OEA) is a high-impact, open access, peer reviewed monthly SCI journal with an impact factor of 9.682 (Journals Citation Reports for IF 2020). Since its launch in March 2018, OEA has been indexed in SCI, EI, DOAJ, Scopus, CA and ICI databases over the time and expanded its Editorial Board to 36 members from 17 countries and regions (average h-index 49).
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