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
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
针对传统相位差分法在振动定位中因信噪比不足导致的定位精度低和信号恢复困难问题,提出一种基于相位敏感光时域反射仪(Φ-OTDR)的滑动方差变分模态分解(SV-VMD)振动定位及信号恢复方法。SV算法通过滑动窗口计算相位差分方差,选取振动点...针对传统相位差分法在振动定位中因信噪比不足导致的定位精度低和信号恢复困难问题,提出一种基于相位敏感光时域反射仪(Φ-OTDR)的滑动方差变分模态分解(SV-VMD)振动定位及信号恢复方法。SV算法通过滑动窗口计算相位差分方差,选取振动点前10 m的相位作为修正参考相位,有效抑制累积噪声;VMD通过多尺度分解分离有效信号分量与趋势噪声,消除正交解调引入的直流偏移。实验结果表明:与传统相位差分法相比,SV算法使系统信噪比提升12 d B(从14 d B至26 d B),并在多振动源场景下清晰分辨了400 m和650 m处的干扰事件;经参数优化(惩罚因子α=100,模式数K=3)的VMD算法成功恢复了三角波信号,显著抑制了非振动相关噪声。展开更多
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.
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.
文摘针对传统相位差分法在振动定位中因信噪比不足导致的定位精度低和信号恢复困难问题,提出一种基于相位敏感光时域反射仪(Φ-OTDR)的滑动方差变分模态分解(SV-VMD)振动定位及信号恢复方法。SV算法通过滑动窗口计算相位差分方差,选取振动点前10 m的相位作为修正参考相位,有效抑制累积噪声;VMD通过多尺度分解分离有效信号分量与趋势噪声,消除正交解调引入的直流偏移。实验结果表明:与传统相位差分法相比,SV算法使系统信噪比提升12 d B(从14 d B至26 d B),并在多振动源场景下清晰分辨了400 m和650 m处的干扰事件;经参数优化(惩罚因子α=100,模式数K=3)的VMD算法成功恢复了三角波信号,显著抑制了非振动相关噪声。
