Φ-OTDR分布式光纤振动传感系统稳定性研究
发布时间：2021-04-18 07:45
分布式光纤传感技术为基础设施的结构健康监测提供了一种高效、经济的解决方案。该技术可应用于长距离的振动检测领域,如石化管道、电力线缆、铁路轨道、周界安防和地震检测等。近年来,相位敏感光时域反射计（Φ-OTDR）作为分布式光纤传感技术的典型代表,以其结构简单、灵敏度高、响应速度快、铺设方案简单等优点,越来越受到人们的重视。Φ-OTDR系统借助对外界振动极为敏感的激光相位信息来实现振动事件的感知,但环境噪声和器件噪声常会对系统的稳定性产生影响,具体表现在以下三个方面:激光光源频率漂移所造成的输出不稳定现象,激光功率放大非线性效应所形成的调制不稳定现象,以及激光相位正交解调不平衡所引起的还原不稳定现象。以上系统的不稳定因素会对Φ-OTDR系统的传感距离、频响范围、误报概率产生较大的影响。针对系统的以上问题,本文的主要研究内容与创新工作如下:（1）提出了一种用于低频振动检测的自适应脉冲调制技术。通过使探测脉冲光的脉冲重复频率进行自适应变化,使振动引起的相位变化频率低于脉冲重复频率,从而在振动区域实现了稳定的强度变化。实验中,使用了两种不同的脉冲重复频率来验证自适应脉冲调制方法检测低频振动事件的有...
【文章来源】：太原理工大学山西省 211工程院校
【文章页数】：141 页
【学位级别】：博士
【文章目录】：
ABSTRACT
摘要
Chapter 1:Introduction
1.1 Optical fiber sensors
1.1.1 Interferometric fiber-optic sensors
1.1.2 Optical time domain reflectometry
1.2 Performance enhancement in Φ-OTDR based vibration sensor systems
1.2.1 Methods and techniques for improvement of the SNR in Φ-OTDR sensor systems
1.2.2 Configurations of Φ-OTDR systems for large sensing range
1.2.3 Φ-OTDR systems with spatial resolution in the sub-meter range
1.2.4 Φ-OTDR systems with frequency response bandwidth higher than the limit set by the sensing range
1.2.5 Φ-OTDR systems for recovery of the full vector information of the external vibrations
1.3 Conclusion
Chapter 2:Adaptive pulse modulation in intensity-based Φ-OTDR systems for low-frequency vibration measurement
2.1 Noise characterization in Φ-OTDR sensor system
2.1.1 Noise in laser source
2.1.2 Finite extinction ratio of the optical modulator
2.1.3 Other noise sources
2.2 Adaptive pulse modulation method（APM） and low-frequency vibrations measurement
2.2.1 Principle of the adaptive pulse modulation method
2.2.2 Low-frequency vibrations measurement method
2.2.3 Experimental results
2.3 APM method in direct detection Φ-OTDR for low-frequency events detection
2.3.1 Discussion
2.4 Conclusions
Chapter 3:Modulation instability and probe pulse waveform in Φ-OTDR sensor system
3.1 Introduction
3.1.1 Optical fiber modes
3.1.2 Dispersion in SMF
3.1.3 Nonlinear effects in SMFs
3.2 Pulse propagation in optical fibers
3.2.1 Modulation instability（MI）and Fermi-Pasta-Ulam（FPU）recurrence
3.2.2 Influence of the MI on the performance of the Φ-OTDR system
3.3 Impact of the waveform of the probe pulse on the performance of Φ-OTDR system
3.4 Conclusions
Chapter 4:Accuracy of coherent Φ-OTDR system for vibration measurement using I/Q demodulation
4.1 Introduction
4.2 Coherent detection
4.2.1 SNR improvement using the coherent detection
4.2.2 I/Q demodulation
4.3 I/Q quadrature imbalances
4.3.1 Different methods used for the compensation of the I/Q quadrature imbalance phenomenon
4.4 Coherent optical pulse phase rotation reflectometry（COPPRR）system insensitive to I/Q quadrature imbalance with enhanced SNR
4.4.1 Principle of the COPPRR system
4.4.2 Experimental results
4.5 Discussion
4.6 Conclusions
Chapter 5:Conclusions and Recommendation for future works
5.1 Conclusions
5.2 Recommendations for future works
References
List of figures
List of Tables
Acknowledgements
SCIENTIFIC RESEARCH ACHIEVEMENTS AND PROJECT EXPERIENCES DURING DOCTORAL STUDIES
【参考文献】：
期刊论文
[1]长距离分布式光纤传感技术研究进展[J]. 饶云江. 物理学报. 2017(07)
[2]相位敏感光时域反射仪研究和应用进展[J]. 叶青,潘政清,王照勇,卢斌,魏芳,瞿荣辉,蔡海文,赵浩,方祖捷. 中国激光. 2017(06)
[3]调制器消光比对光纤分布式扰动传感器的影响[J]. 李勤,张春熹,李立京,梁生,钟翔,李传生. 光电子.激光. 2014(04)
本文编号：3145106
【文章来源】：太原理工大学山西省 211工程院校
【文章页数】：141 页
【学位级别】：博士
【文章目录】：
ABSTRACT
摘要
Chapter 1:Introduction
1.1 Optical fiber sensors
1.1.1 Interferometric fiber-optic sensors
1.1.2 Optical time domain reflectometry
1.2 Performance enhancement in Φ-OTDR based vibration sensor systems
1.2.1 Methods and techniques for improvement of the SNR in Φ-OTDR sensor systems
1.2.2 Configurations of Φ-OTDR systems for large sensing range
1.2.3 Φ-OTDR systems with spatial resolution in the sub-meter range
1.2.4 Φ-OTDR systems with frequency response bandwidth higher than the limit set by the sensing range
1.2.5 Φ-OTDR systems for recovery of the full vector information of the external vibrations
1.3 Conclusion
Chapter 2:Adaptive pulse modulation in intensity-based Φ-OTDR systems for low-frequency vibration measurement
2.1 Noise characterization in Φ-OTDR sensor system
2.1.1 Noise in laser source
2.1.2 Finite extinction ratio of the optical modulator
2.1.3 Other noise sources
2.2 Adaptive pulse modulation method（APM） and low-frequency vibrations measurement
2.2.1 Principle of the adaptive pulse modulation method
2.2.2 Low-frequency vibrations measurement method
2.2.3 Experimental results
2.3 APM method in direct detection Φ-OTDR for low-frequency events detection
2.3.1 Discussion
2.4 Conclusions
Chapter 3:Modulation instability and probe pulse waveform in Φ-OTDR sensor system
3.1 Introduction
3.1.1 Optical fiber modes
3.1.2 Dispersion in SMF
3.1.3 Nonlinear effects in SMFs
3.2 Pulse propagation in optical fibers
3.2.1 Modulation instability（MI）and Fermi-Pasta-Ulam（FPU）recurrence
3.2.2 Influence of the MI on the performance of the Φ-OTDR system
3.3 Impact of the waveform of the probe pulse on the performance of Φ-OTDR system
3.4 Conclusions
Chapter 4:Accuracy of coherent Φ-OTDR system for vibration measurement using I/Q demodulation
4.1 Introduction
4.2 Coherent detection
4.2.1 SNR improvement using the coherent detection
4.2.2 I/Q demodulation
4.3 I/Q quadrature imbalances
4.3.1 Different methods used for the compensation of the I/Q quadrature imbalance phenomenon
4.4 Coherent optical pulse phase rotation reflectometry（COPPRR）system insensitive to I/Q quadrature imbalance with enhanced SNR
4.4.1 Principle of the COPPRR system
4.4.2 Experimental results
4.5 Discussion
4.6 Conclusions
Chapter 5:Conclusions and Recommendation for future works
5.1 Conclusions
5.2 Recommendations for future works
References
List of figures
List of Tables
Acknowledgements
SCIENTIFIC RESEARCH ACHIEVEMENTS AND PROJECT EXPERIENCES DURING DOCTORAL STUDIES
【参考文献】：
期刊论文
[1]长距离分布式光纤传感技术研究进展[J]. 饶云江. 物理学报. 2017(07)
[2]相位敏感光时域反射仪研究和应用进展[J]. 叶青,潘政清,王照勇,卢斌,魏芳,瞿荣辉,蔡海文,赵浩,方祖捷. 中国激光. 2017(06)
[3]调制器消光比对光纤分布式扰动传感器的影响[J]. 李勤,张春熹,李立京,梁生,钟翔,李传生. 光电子.激光. 2014(04)
本文编号：3145106
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