分布式光纖傳感技術(shù)為基礎(chǔ)設(shè)施的結(jié)構(gòu)健康監(jiān)測提供了一種高效、經(jīng)濟(jì)的解決方案。該技術(shù)可應(yīng)用于長距離的振動(dòng)檢測領(lǐng)域,如石化管道、電力線纜、鐵路軌道、周界安防和地震檢測等。近年來,相位敏感光時(shí)域反射計(jì)（Φ-OTDR）作為分布式光纖傳感技術(shù)的典型代表,以其結(jié)構(gòu)簡單、靈敏度高、響應(yīng)速度快、鋪設(shè)方案簡單等優(yōu)點(diǎn),越來越受到人們的重視。Φ-OTDR系統(tǒng)借助對外界振動(dòng)極為敏感的激光相位信息來實(shí)現(xiàn)振動(dòng)事件的感知,但環(huán)境噪聲和器件噪聲常會對系統(tǒng)的穩(wěn)定性產(chǎn)生影響,具體表現(xiàn)在以下三個(gè)方面:激光光源頻率漂移所造成的輸出不穩(wěn)定現(xiàn)象,激光功率放大非線性效應(yīng)所形成的調(diào)制不穩(wěn)定現(xiàn)象,以及激光相位正交解調(diào)不平衡所引起的還原不穩(wěn)定現(xiàn)象。以上系統(tǒng)的不穩(wěn)定因素會對Φ-OTDR系統(tǒng)的傳感距離、頻響范圍、誤報(bào)概率產(chǎn)生較大的影響。針對系統(tǒng)的以上問題,本文的主要研究內(nèi)容與創(chuàng)新工作如下:（1）提出了一種用于低頻振動(dòng)檢測的自適應(yīng)脈沖調(diào)制技術(shù)。通過使探測脈沖光的脈沖重復(fù)頻率進(jìn)行自適應(yīng)變化,使振動(dòng)引起的相位變化頻率低于脈沖重復(fù)頻率,從而在振動(dòng)區(qū)域?qū)崿F(xiàn)了穩(wěn)定的強(qiáng)度變化。實(shí)驗(yàn)中,使用了兩種不同的脈沖重復(fù)頻率來驗(yàn)證自適應(yīng)脈沖調(diào)制方法檢測低頻振動(dòng)事件的有... 

【文章來源】：太原理工大學(xué)山西省 211工程院校

【文章頁數(shù)】：141 頁

【學(xué)位級別】：博士

【文章目錄】：
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


【參考文獻(xiàn)】：
期刊論文
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[2]相位敏感光時(shí)域反射儀研究和應(yīng)用進(jìn)展[J]. 葉青,潘政清,王照勇,盧斌,魏芳,瞿榮輝,蔡海文,趙浩,方祖捷.  中國激光. 2017(06)
[3]調(diào)制器消光比對光纖分布式擾動(dòng)傳感器的影響[J]. 李勤,張春熹,李立京,梁生,鐘翔,李傳生.  光電子.激光. 2014(04)



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