BOTDA系统关键技术的理论和实验研究

发布时间：2018-06-01 05:46

本文选题：布里渊光时域分析 + 脉冲预泵浦　；参考：《华北电力大学》2015年硕士论文

【摘要】：本文综述了布里渊分布式光纤传感技术的研究现状,论述了光纤中的布里渊散射及其特征参数,研究了布里渊频移与光纤温度和应变的对应关系,根据布里渊光时域分析(BOTDA)系统中布里渊频移的温度和应变交叉敏感特性,总结了三种同时实现温度和应变测量的方法。根据受激布里渊散射(SBS)的作用机理,分析了其稳态耦合波方程和瞬态耦合波方程。介绍了偏振光相关基本理论,在理论分析电光调制器(EOM)的内部结构、输入输出关系数学表达式及其偏振相关特性的基础上,设计了BOTDA中EOM输入光的偏振控制系统。推导了挤压光纤型偏振控制器光偏振态的输入输出关系数学表达式,建立了EOM输入光自适应偏振控制系统数学模型;理论分析了PID工业控制算法并首次提出将其应用于偏振控制系统中,并选择了其参数整定方法,设计并编写了PID偏振控制算法程序,搭建了基于LabVIEW的偏振控制系统软件平台;搭建了基于数据采集与控制的偏振控制系统硬件平台。理论分析并实验验证了该方法的可行性。实验结果表明,基于该方法设计的控制系统不仅能实时监测EOM输出光功率,而且能保持其输出光功率最大;与激光器和EOM输入端直接用保偏光纤连接时相比,PID偏振控制下EOM输出平均功率提高了3.08 dB,PD输出电压标准差由0.1214降至1.2375×10-4,稳定控制状态下偏振态矫正时间在ms量级,满足BOTDA的偏振控制系统要求。分析了脉冲预泵浦BOTDA传感系统原理,利用差分增益法对脉冲预泵浦BOTDA的瞬态耦合波方程进行解析,并对传感系统进行了设计。
[Abstract]:In this paper, the research status of Brillouin distributed fiber sensing technology is reviewed, the Brillouin scattering and its characteristic parameters are discussed, and the relationship between Brillouin frequency shift and fiber temperature and strain is studied. According to the characteristics of temperature and strain cross sensitivity of Brillouin frequency shift in BOTDA system, three methods for simultaneous measurement of temperature and strain are summarized. According to the mechanism of stimulated Brillouin scattering (SBS), the steady-state coupled wave equation and transient coupled wave equation are analyzed. The basic theory of polarized light correlation is introduced. Based on the theoretical analysis of the internal structure of the electro-optic modulator EOM, the mathematical expression of the input and output relations and the polarization correlation characteristics, the polarization control system of the EOM input light in BOTDA is designed. The mathematical expression of the input and output relationship of the polarization state of the squeezed fiber polarization controller is derived, and the mathematical model of the adaptive polarization control system of the EOM input light is established. The PID industrial control algorithm is analyzed theoretically and applied to the polarization control system for the first time. The parameter setting method is selected, the PID polarization control algorithm program is designed and written, and the software platform of the polarization control system based on LabVIEW is built. The hardware platform of polarization control system based on data acquisition and control is built. The feasibility of the method is verified by theoretical analysis and experiments. The experimental results show that the control system based on this method can not only monitor the output optical power of EOM in real time, but also maintain the maximum output optical power. Compared with that when the laser and EOM input are connected directly by polarization maintaining fiber, the average output power of EOM under pid polarization control is increased from 0.1214 to 1.2375 脳 10 ~ (-4), and the correction time of polarization state is in the order of Ms under stable control condition, and the output voltage standard deviation of EOM is decreased from 0.1214 to 1.2375 脳 10 ~ (-4). Meet the requirements of BOTDA polarization control system. The principle of pulse prepumped BOTDA sensing system is analyzed, and the transient coupled wave equation of pulse prepumped BOTDA is analyzed by differential gain method, and the sensing system is designed.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253

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