【摘要】：由于光纖材料的不均勻性,光波在光纖中傳輸時將產(chǎn)生瑞利散射。利用瑞利散射光的分布式光纖傳感技術已在周界安防、輸油管道、高鐵等結構安全健康監(jiān)測領域發(fā)揮出重要作用。其中,基于相位解調的Φ-OTDR作為一種新型分布式聲波傳感系統(tǒng),已成為目前光纖傳感領域國內外的研究熱點,其在石油勘探,地質結構分析等領域展現(xiàn)出不可忽視的優(yōu)越性和巨大市場前景。然而,目前Φ-OTDR系統(tǒng)的相位解調方案在靈敏度、實時性和穩(wěn)定性等方面都存在其固有缺陷。本文通過在Φ-OTDR系統(tǒng)中引入新的相位解調方式——基于90。光學混頻器的相位解調,利用光纖中的瑞利散射光的相位解調實現(xiàn)分布式聲波傳感,克服了幾種現(xiàn)有的相位解調方式存在的缺陷,對擴展Φ-OTDR應用、提升DAS性能具有重要意義�，F(xiàn)將本文具體工作介紹如下：1.本文介紹了光纖中瑞利散射光以及基于瑞利散射光的分布式傳感技術——Φ-OTDR的相關理論基礎,包括：光纖中瑞利散射光相關原理；Φ-OTDR傳感原理和幾種現(xiàn)有的Φ-OTDR相位解調方案。2.本文提出基于90。光學混頻器的瑞利散射光相位解調方式,并簡述其解調原理和基于此解調方式的Φ-OTDR聲波傳感原理。3.本文進行了基于90。光學混頻器搭建的外差檢測的Φ-OTDR相位解調實驗,實驗證明基于此解調方案能夠實現(xiàn)光纖中瑞利散射光的相位解調,且基于此方案的Φ-OTDR能夠進行分布式聲波傳感。4. 本文搭建了基于零差檢測的90。光學混頻器的Φ-OTDR系統(tǒng),并進行聲波傳感實驗：分別利用自行編寫的MATLAB程序和LABVIEW程序進行了離線和在線的分布式聲波傳感系統(tǒng)聲波擾動實驗；實驗進一步證明基于90。光學混頻器的相位解調方案的可行性,并對系統(tǒng)的頻率響應平坦度和系統(tǒng)對不同聲波振幅響應的線性度做了簡要分析。5.本文對比了基于90°光學混頻器的相位解調方案和現(xiàn)有的其他幾種相位解調方案,得出基于90°光學混頻器的相位解調的Φ-OTDR在聲波傳感方面具有系統(tǒng)穩(wěn)定,實時性高,靈敏度高等優(yōu)點的結論。
[Abstract]:Due to the inhomogeneity of fiber materials, Rayleigh scattering will occur when light waves propagate in optical fibers. The distributed optical fiber sensing technology using Rayleigh scattering light has played an important role in the field of perimeter security, oil pipeline, high iron and other structural safety and health monitoring. As a new distributed acoustic sensing system, 桅 -OTDR based on phase demodulation has become a hot spot in the field of optical fiber sensing. Geological structure analysis and other fields show great advantages and huge market prospects. However, the phase demodulation scheme of 桅 -OTDR system has its inherent defects in sensitivity, real-time and stability. This paper introduces a new phase demodulation method in 桅 -OTDR system based on 90. The phase demodulation of optical mixer, using Rayleigh scattering light in optical fiber to realize distributed acoustic sensing, overcomes the defects of several existing phase demodulation methods, and is of great significance to expand 桅 -OTDR application and improve the performance of DAS. The specific work of this article is introduced as follows: 1. This paper introduces the theoretical basis of Rayleigh scattering light in optical fiber and the distributed sensing technology-桅 -OTDR based on Rayleigh scattering light, including: correlation principle of Rayleigh scattering light in optical fiber, 桅 -OTDR sensing principle and several existing 桅 -OTDR phase demodulation schemes. In this paper, based on 90. The phase demodulation method of Rayleigh scattering light for optical mixers is presented. The demodulation principle and the principle of 桅 -OTDR acoustic wave sensing based on this demodulation method are briefly described. In this paper, based on 90. The 桅 -OTDR phase demodulation experiment of heterodyne detection built by optical mixer shows that this demodulation scheme can realize the phase demodulation of Rayleigh scattering light in optical fiber, and the 桅 -OTDR based on this scheme can carry out distributed acoustic wave sensing. 4. In this paper, a 90. 0 based on homodyne detection is built. The 桅 -OTDR system of optical mixer, and the acoustic wave sensing experiment: using the MATLAB program and LABVIEW program written by ourselves, the acoustic disturbance experiment of off-line and on-line distributed acoustic wave sensing system is carried out, which is further proved to be based on 90. The feasibility of the phase demodulation scheme of the optical mixer is discussed. The flatness of the frequency response of the system and the linearity of the response of the system to different acoustic amplitudes are analyzed briefly. In this paper, the phase demodulation scheme based on 90 擄optical mixer and several other phase demodulation schemes are compared. It is concluded that 桅 -OTDR based on 90 擄optical mixer is stable and real-time in acoustic sensing. A conclusion of high sensitivity.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TN253

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相關碩士學位論文 前1條

1 劉暢;3×3耦合器解調方法研究與實現(xiàn)[D];哈爾濱工程大學;2012年

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本文編號：2160066