光纤磁场传感器信号处理研究-光学工程专业论文.docxVIP

电子科技大学硕士论文 电子科技大学硕士论文 I I 摘 要 光纤磁场传感器探磁灵敏度高，可应用于国防，工农业，医学各个领域。论 文对光纤磁场传感器的发展及研究现状进行了介绍。本文主要内容如下： 首先，应用 Jones 矩阵法对法拉第旋转镜（FRM）消除光纤干涉仪偏振衰落 的原理作了分析。简要介绍了偏振无关 Michelson 干涉仪光纤磁场传感器系统原 理。对传感器信号及传感系统噪声进行了分析，提出了减小噪声的各种方法。 鉴于简单遗传算法处理信号的速度较慢，本文利用保留最佳值方法及进化过 程中种群质量判断等方法对简单遗传算法进行了改进，提高了信号处理的速度。 仿真结果证明，遗传算法可以一次性提取传感信号和干涉仪工作点信息，并且传 感信号的提取与工作点基本无关。在 SNR≥10 的条件下，改进的遗传算法可以 准确提取信号，特别适合非线性、大信号情况的信号处理。 其次，针对传感器相位受环境影响随机变化导致信号衰落问题，提出了 f-2f 闭环控制工作点方法。分析了该方法对光纤磁场传感器进行主动相位补偿的工作 原理；设计了闭环控制流程；并通过实验对其进行验证。实验结果表明工作点得 到了稳定的控制，磁场传感信号稳定性好、线性度高、响应速度快。 此外，本文还介绍了外调制 PGC 技术的原理，分析了相位载波调制的信号 特征，并进行了实验测量，分析了存在的问题。 最后，对本文所作的工作进行总结，对光纤磁场传感器进一步的改进提出了 建议。 关键词：光纤传感器；Mi chel son 干涉仪；遗传算法；相位载波调制技术； 磁场测量 II II Abstract The optical fiber magnetic field sensor has high magnetic-sensing sensitivity, and can be used in national defence, industry, agriculture, and medicine fields. The development and current research status of optical fiber magnetic field sensor are outlined in this thesis. The main contents of this thesis are as follows: Firstly, the principle of eliminating polarization-induced fading in fiber interferometer with Faraday Rotator Mirrors (FRM) is analyzed by Jones matrix method. The optical fiber magnetic field sensor system based on polarization-insensitive Michelson interferometer is presented. In this thesis we analyze the sensing signal and sensor system noise, and bring forward methods of decreasing noises. Secondly, because of slow speed in sensor signal processing by Simple Genetic Algorithm, the methods of elitist model and quality judgment of population are used to improve Simple Genetic Algorithm and accelerate signal processing speed. The emulational results indicate: picking up sensor information and interferometer working point can be finished at the same time, and sensing signal is independent with working point. The sensing signal can be exactly obtained by the improved Genetic Algorithm, it adapts especially to the nonlinear and large signals when SNR≥10. Thirdly, aiming at the si