本文選題：分布式光纖傳感　切入點：BOTDA系統(tǒng)　出處：《華北電力大學》2016年碩士論文

【摘要】：本文綜述了分布式光纖傳感技術近年來研究方向,并詳細論述了瑞利布里淵光時域分析(R-BOTDA)系統(tǒng)國內外發(fā)展研究現狀。理論上詳細研究了BOTDA系統(tǒng)的技術原理;分析了受激布里淵散射(SBS)穩(wěn)態(tài)耦合波方程和瞬態(tài)耦合波方程,以及布里淵頻移與光纖溫度、應變的關系。針對BOTDA系統(tǒng)受非本地效應影響,分析研究了泵浦光能量損耗和光纖長度、探測光功率之間的關系,定量分析了光纖長度、探測光功率和BOTDA系統(tǒng)中非本地效應引起的測量誤差之間的關系。對SMF光纖的仿真研究表明:當光纖長度為2000m時,非本地效應會引起1.5℃的溫度誤差、30με的應變誤差。為改善BOTDA系統(tǒng)中非本地效應對系統(tǒng)的影響,本文構建了一種脈沖預泵浦瑞利BOTDA系統(tǒng)(PPP-RBOTDA),運用預泵浦脈沖1階邊帶激發(fā)的瑞利散射光做探測光,使得瑞利散射光分別與預泵浦脈沖的0階基帶和傳感脈沖發(fā)生受激布里淵作用,通過檢測散射回來的瑞利光信號獲取光纖的溫度和應變信息。建立了瞬態(tài)條件下脈沖預泵浦和傳感脈沖發(fā)生SBS作用的數學模型,對階梯脈沖進行了最佳化設計,運用Matlab軟件仿真研究表明當傳感脈沖為50mw、6ns,預泵浦脈沖為500mW、100ns時,可獲得滿足PPP-RBOTDA系統(tǒng)要求的瑞利散射光,且瑞利散射光發(fā)生SBS作用產生的FWHM為布里淵自然增益線寬34MHz,能有效減小瞬態(tài)SBS作用下FWHM的展寬效應,提高系統(tǒng)的頻譜分辨率。探討了EOM用于PPP-RBOTDA系統(tǒng)時的最佳工作點問題;運用Opti System軟件進行仿真研究,驗證了EOM調制產生的預泵浦信號含有0階基帶和1階邊帶信號。搭建了實驗系統(tǒng),合成了階梯脈沖;通過對EOM射頻端進行掃頻操作,對瑞利散射信號進行采集處理后,成功擬合出了布里淵損耗譜曲線。
[Abstract]:In this paper, the research direction of distributed optical fiber sensing technology in recent years is reviewed, and the research status of Rayleigh Brillouin optical time domain analysis (R-BOTDA) system at home and abroad is discussed in detail. The technical principle of BOTDA system is studied in theory. The steady-state coupled wave equation and transient coupled wave equation of stimulated Brillouin scattering (SBS), and the relationship between Brillouin frequency shift and fiber temperature and strain are analyzed. The relationship between the energy loss of pump light and the length of the fiber and the power of the probe light is analyzed and the length of the optical fiber is quantitatively analyzed. The relationship between the detecting optical power and the measurement error caused by the non-native effect in the BOTDA system. The simulation results of the SMF fiber show that when the length of the fiber is 2000m, In order to improve the influence of non-native effect on BOTDA system, the temperature error of 1.5 鈩，

本文編號：1673334