Phase-sensitive optical time domain reflectometry(Ф-OTDR)is an effective way to detect vibrations and acoustic waves with high sensitivity,by interrogating coherent Rayleigh backscattering light in sensing fiber.In p...Phase-sensitive optical time domain reflectometry(Ф-OTDR)is an effective way to detect vibrations and acoustic waves with high sensitivity,by interrogating coherent Rayleigh backscattering light in sensing fiber.In particular,fiber-optic distributed acoustic sensing(DAS)based on theФ-OTDR with phase demodulation has been extensively studied and widely used in intrusion detection,borehole seismic acquisition,structure health monitoring,etc.,in recent years,with superior advantages such as long sensing range,fast response speed,wide sensing bandwidth,low operation cost and long service lifetime.Significant advances in research and development(R&D)ofФ-OTDR have been made since 2014.In this review,we present a historical review ofФ-OTDR and then summarize the recent progress ofФ-OTDR in the Fiber Optics Research Center(FORC)at University of Electronic Science and Technology of China(UESTC),which is the first group to carry out R&D ofФ-OTDR and invent ultra-sensitive DAS(uDAS)seismometer in China which is elected as one of the ten most significant technology advances of PetroChina in 2019.It can be seen that theФ-OTDR/DAS technology is currently under its rapid development stage and would reach its climax in the next 5 years.展开更多
The application of Golay pulse coding technique in spontaneous Brillouin-based distributed temperature sensor based on self-heterodyne detection of Rayleigh and Brillouin scattering is theoretically and experimentally...The application of Golay pulse coding technique in spontaneous Brillouin-based distributed temperature sensor based on self-heterodyne detection of Rayleigh and Brillouin scattering is theoretically and experimentally analyzed. The enhancement of system signal to noise ratio(SNR) and reduction of temperature measurement error provided by coding are characterized. By using 16-bit Golay coding, SNR can be improved by about 2.77 d B, and temperature measurement error of the 100 m heated fiber is reduced from 1.4 °C to 0.5 °C with a spatial resolution of 13 m. The results are believed to be beneficial for the performance improvement of self-heterodyne detection Brillouin optical time domain reflectometer.展开更多
随着电力通信网络的不断发展,光缆作为传输介质的可靠性受到极大关注。光缆故障不仅会影响通信的稳定性,还会给电力系统的正常运行带来不利影响。因此,快速且准确地定位光缆故障点,并及时处理,已成为电力通信网络管理的重要任务。光时...随着电力通信网络的不断发展,光缆作为传输介质的可靠性受到极大关注。光缆故障不仅会影响通信的稳定性,还会给电力系统的正常运行带来不利影响。因此,快速且准确地定位光缆故障点,并及时处理,已成为电力通信网络管理的重要任务。光时域反射仪(Optical Time Domain Reflectometer,OTDR)曲线事件分析技术是光缆故障定位的核心技术。文章通过分析OTDR曲线事件分析技术,研究改进OTDR曲线事件分析技术,结合地理信息系统(Geographic Information System,GIS)技术设计电力通信光缆故障精确定位方案,并针对不同故障提出相应的处置对策。本研究旨在为电力通信网络中的光缆故障检测与定位提供技术支持,同时为提升电力通信网络的稳定性和可靠性提供理论依据。展开更多
分布式光纤传感技术具有大检测范围、长距离传输、高灵敏度等特点,在油气管道泄漏检测、周界入侵以及地球物理科学等中有着极为广泛的应用。研究了直接探测型相敏光时域反射仪中探测器检测带宽对空间分辨率和噪声基底的影响,采用不同检...分布式光纤传感技术具有大检测范围、长距离传输、高灵敏度等特点,在油气管道泄漏检测、周界入侵以及地球物理科学等中有着极为广泛的应用。研究了直接探测型相敏光时域反射仪中探测器检测带宽对空间分辨率和噪声基底的影响,采用不同检测带宽的探测器对原始信号进行采集,绘制了外部扰动事件响应的强度图。结果表明,光电探测器检测带宽为12.5 MHz的相敏光时域反射系统中,噪声基底低至-61 dB rad2/Hz,且对空间分辨率的影响小于3 m。该研究为进一步发展高灵敏度的基于直接探测型相敏光时域反射仪的分布式光纤传感系统提供了重要参考。展开更多
当前通信光缆故障检测时,主要通过单向光时域反射仪(Optical Time Domain Reflectometer,OTDR)测试获取光缆运行数据,但仪表测试距离的限制会影响采集数据的完整程度,导致故障智能检测结果F1值较低。因此,提出一种以双向OTDR测试为核心...当前通信光缆故障检测时,主要通过单向光时域反射仪(Optical Time Domain Reflectometer,OTDR)测试获取光缆运行数据,但仪表测试距离的限制会影响采集数据的完整程度,导致故障智能检测结果F1值较低。因此,提出一种以双向OTDR测试为核心的通信光缆故障智能检测方法。应用多个光时域反射仪建立双向OTDR测试方案,实时采集通信光缆运行数据,并结合双向拉曼分布式放大技术,弥补光纤传输损耗。依托于小波变换算法分解测试信号,从时域和频域2个方面提取光缆运行信号特征。利用故障树概念构建通信光缆故障树,检测出当前通信光缆存在故障类型,并定位故障点具体位置。实验结果表明:所提方法应用后,得出的通信光缆故障智能检测结果F1值为0.93,满足智能检测精度要求。展开更多
基金The authors would like to thank all of the members in the FORC at UESTC for their hard work and important contributions to this workThis work was funded by the Natural Science Foundation of China(Grant Nos.41527805 and 61635005)the 111 Poject(Grant No.B14039).
文摘Phase-sensitive optical time domain reflectometry(Ф-OTDR)is an effective way to detect vibrations and acoustic waves with high sensitivity,by interrogating coherent Rayleigh backscattering light in sensing fiber.In particular,fiber-optic distributed acoustic sensing(DAS)based on theФ-OTDR with phase demodulation has been extensively studied and widely used in intrusion detection,borehole seismic acquisition,structure health monitoring,etc.,in recent years,with superior advantages such as long sensing range,fast response speed,wide sensing bandwidth,low operation cost and long service lifetime.Significant advances in research and development(R&D)ofФ-OTDR have been made since 2014.In this review,we present a historical review ofФ-OTDR and then summarize the recent progress ofФ-OTDR in the Fiber Optics Research Center(FORC)at University of Electronic Science and Technology of China(UESTC),which is the first group to carry out R&D ofФ-OTDR and invent ultra-sensitive DAS(uDAS)seismometer in China which is elected as one of the ten most significant technology advances of PetroChina in 2019.It can be seen that theФ-OTDR/DAS technology is currently under its rapid development stage and would reach its climax in the next 5 years.
基金supported by the National Natural Science Foundation of China(No.61377088)the Natural Science Foundation of Hebei Province of China(Nos.E2015502053 and F2014502098)
文摘The application of Golay pulse coding technique in spontaneous Brillouin-based distributed temperature sensor based on self-heterodyne detection of Rayleigh and Brillouin scattering is theoretically and experimentally analyzed. The enhancement of system signal to noise ratio(SNR) and reduction of temperature measurement error provided by coding are characterized. By using 16-bit Golay coding, SNR can be improved by about 2.77 d B, and temperature measurement error of the 100 m heated fiber is reduced from 1.4 °C to 0.5 °C with a spatial resolution of 13 m. The results are believed to be beneficial for the performance improvement of self-heterodyne detection Brillouin optical time domain reflectometer.
文摘随着电力通信网络的不断发展,光缆作为传输介质的可靠性受到极大关注。光缆故障不仅会影响通信的稳定性,还会给电力系统的正常运行带来不利影响。因此,快速且准确地定位光缆故障点,并及时处理,已成为电力通信网络管理的重要任务。光时域反射仪(Optical Time Domain Reflectometer,OTDR)曲线事件分析技术是光缆故障定位的核心技术。文章通过分析OTDR曲线事件分析技术,研究改进OTDR曲线事件分析技术,结合地理信息系统(Geographic Information System,GIS)技术设计电力通信光缆故障精确定位方案,并针对不同故障提出相应的处置对策。本研究旨在为电力通信网络中的光缆故障检测与定位提供技术支持,同时为提升电力通信网络的稳定性和可靠性提供理论依据。
文摘分布式光纤传感技术具有大检测范围、长距离传输、高灵敏度等特点,在油气管道泄漏检测、周界入侵以及地球物理科学等中有着极为广泛的应用。研究了直接探测型相敏光时域反射仪中探测器检测带宽对空间分辨率和噪声基底的影响,采用不同检测带宽的探测器对原始信号进行采集,绘制了外部扰动事件响应的强度图。结果表明,光电探测器检测带宽为12.5 MHz的相敏光时域反射系统中,噪声基底低至-61 dB rad2/Hz,且对空间分辨率的影响小于3 m。该研究为进一步发展高灵敏度的基于直接探测型相敏光时域反射仪的分布式光纤传感系统提供了重要参考。
文摘当前通信光缆故障检测时,主要通过单向光时域反射仪(Optical Time Domain Reflectometer,OTDR)测试获取光缆运行数据,但仪表测试距离的限制会影响采集数据的完整程度,导致故障智能检测结果F1值较低。因此,提出一种以双向OTDR测试为核心的通信光缆故障智能检测方法。应用多个光时域反射仪建立双向OTDR测试方案,实时采集通信光缆运行数据,并结合双向拉曼分布式放大技术,弥补光纤传输损耗。依托于小波变换算法分解测试信号,从时域和频域2个方面提取光缆运行信号特征。利用故障树概念构建通信光缆故障树,检测出当前通信光缆存在故障类型,并定位故障点具体位置。实验结果表明:所提方法应用后,得出的通信光缆故障智能检测结果F1值为0.93,满足智能检测精度要求。
