铌酸锂波导电光调制器偏压控制及在BOTDA系统中的应用

发布时间：2018-04-16 07:49

本文选题：电光调制器 + 自动偏压控制　；参考：《哈尔滨工业大学》2016年硕士论文

【摘要】：分布式光纤传感具有重量轻、体积小、耐腐蚀、电绝缘性好、抗电磁干扰能力强和非入侵性等特点,并且能够同时对几十万个待测点进行测量,由于这一优势,分布式光纤传感在国防军事、能源探测、结构健康检测及工程预警等领域有着广泛的应用前景。采用电光晶体进行光信号调制是分布式光纤传感的核心技术,其调制效果直接影响传感系统的性能,包括测量距离、空间分辨率及精度。然而由于系统中电光调制器易受外界环境因素影响,发生工作点漂移,从而影响整个光纤传感系统的性能。为了解决调制器工作不稳定问题,本文提出一种基于步进和专家PID控制的算法。理论研究调制器的工作原理,搭建偏压控制系统并对该系统在差分脉冲对布里渊光时域分析(DPP-BOTDA)系统中的应用进行了详细的研究,具体内容如下:1、理论研究电光调制器的特性,并进行仿真实验。分析调制器工作点漂移的原因和工作点漂移后对调制信号的影响。分别对BOTDA系统中脉冲调制和微波调制进行了理论分析和仿真研究。2、设计自动偏压系统,对该系统进行实验验证。整个系统包含硬件模块和软件控制,硬件模块包括信号采集模块、信号处理模块、偏置电压输出模块和供电模块;软件部分包括硬件控制和数据算法处理。使用偏压控制系统对调制器进行控制,研究本系统对调制器工作点的锁定效果,包括锁定需要的时间、锁定的精度和锁定的稳定性。3、将所设计的偏压控制系统应用于DPP-BOTDA系统。使用BOTDA系统对悬臂梁的变形进行测试,对采集的数据进行处理,分析获得的布里渊增益谱三维图和布里渊中心频率曲线。
[Abstract]:The distributed optical fiber sensor has the characteristics of light weight, small volume, corrosion resistance, good electrical insulation, strong resistance to electromagnetic interference and non-invasion, and can measure hundreds of thousands of points to be measured at the same time.Distributed optical fiber sensing has a wide application prospect in the fields of defense and military, energy detection, structural health detection and engineering early warning.Optical signal modulation using electro-optic crystals is the core technology of distributed optical fiber sensing. Its modulation effect directly affects the performance of the sensing system, including measurement distance, spatial resolution and accuracy.However, the electro-optic modulator is easy to be affected by external environmental factors, and the operating point drift occurs, which affects the performance of the whole optical fiber sensing system.In order to solve the unstable operation of modulator, an algorithm based on step and expert PID control is proposed in this paper.The working principle of the modulator is studied theoretically, the bias voltage control system is set up and the application of the system in the differential pulse pair Brillouin optical time domain analysis (DPP-BOTDAA) system is studied in detail. The specific contents are as follows: 1. The characteristics of the electro-optic modulator are theoretically studied.And the simulation experiment is carried out.The reason of the modulator's working point drift and the influence of the modulator's working point drift on the modulation signal are analyzed.The theoretical analysis and simulation of pulse modulation and microwave modulation in BOTDA system are carried out, and the automatic bias system is designed and verified by experiments.The whole system includes hardware module and software control, hardware module includes signal acquisition module, signal processing module, bias voltage output module and power supply module; the software part includes hardware control and data algorithm processing.The bias control system is used to control the modulator. The locking effect of the system to the modulator working point is studied, including the locking time, the locking precision and the locking stability. The designed bias control system is applied to the DPP-BOTDA system.The deformation of cantilever beam was measured by BOTDA system, and the collected data were processed. The three dimensional Brillouin gain spectrum and Brillouin center frequency curve were analyzed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN761;TP212

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