用于超弱光纤光栅解调的光电检测电路的研制

发布时间：2018-04-27 02:41

本文选题：超弱光纤光栅解调 + 光电检测　；参考：《北京交通大学》2017年硕士论文

【摘要】：基于超低反射率光纤布拉格光栅的光纤传感系统可以实现长距离、大容量、高空间分辨率的准分布式光纤光栅传感组网,在多参数和多信道分布光纤传输系统中具有广阔的应用前景,是当前光纤传感领域的一个重要研究热点。但由于该系统中所使用的光纤布拉格光栅具有极低的功率反射率(～0.1%),其传感解调系统的光电检测精度和检测灵敏度对整个光纤传感系统所能达到的性能、规模、复用能力以及所能容纳的光纤光栅数量具有决定性的影响。因此对弱光栅光纤传感系统光电检测模块和解调技术的研究,对于该传感系统性能的提升和大规模实际应用具有重要的实际意义和研究价值。基于对超弱光纤光栅传感系统的研究,本文提出了一套完整的符合超弱光纤光栅解调系统要求的光电检测电路的设计方法。主要工作如下:1.使用APD代替PIN光电二极管作为光电探测器以增大电路的增益,选择OPA657作为运算放大器提高电路增益的同时减小引入的噪声;2.前置放大电路后加入RC滤波电路,提高信噪比;3.经计算确定反射信号光功率范围是-25dBm～-33dBm,并设计放大倍数为10k倍的前置放大电路。为保证电路带宽在百兆以上同时保证放大倍数,设计出一级或两级主放大电路,并为每级电路计算最优反馈电阻以及消振电容;4.使用TINA-TI对电路进行仿真和调试并制作光电检测电路实物。实验证明,光电检测电路与超弱光纤光栅解调系统连接后,满足解调要求且性能稳定。
[Abstract]:The fiber optic sensing system based on ultralow reflectivity fiber Bragg grating can realize a long distance, large capacity and high spatial resolution quasi-distributed fiber Bragg grating sensor network. It has a broad application prospect in multi-parameter and multi-channel distributed optical fiber transmission systems, and is an important research hotspot in the field of optical fiber sensing. However, because the fiber Bragg grating used in this system has a very low power reflectivity of 0.1%, the photoelectric detection accuracy and detection sensitivity of the sensing and demodulation system can achieve the performance and scale of the whole optical fiber sensing system. The ability of multiplexing and the number of fiber gratings that can be accommodated have a decisive effect. Therefore, the research on the photoelectric detection module and demodulation technology of the weak grating fiber sensing system has important practical significance and research value for the performance improvement and large-scale practical application of the sensing system. Based on the research of ultra-weak fiber Bragg grating sensing system, this paper presents a complete design method of photoelectric detection circuit which accords with the requirement of ultra-weak fiber grating demodulation system. The main work is as follows: 1. APD is used instead of PIN photodiode as photodetector to increase the circuit gain. OPA657 is chosen as the operational amplifier to increase the circuit gain while reducing the introduced noise. RC filter circuit is added after preamplifier circuit to improve signal-to-noise ratio (SNR). The optical power range of the reflected signal is determined to be -25 dBm-1 -33 dBm, and a preamplifier circuit with 10 k magnification is designed. In order to ensure that the bandwidth of the circuit is more than 100 megabits and the amplification multiple is guaranteed, the primary or two-stage main amplifier circuit is designed, and the optimal feedback resistance and damping capacitance are calculated for each stage circuit. Use TINA-TI to simulate and debug the circuit and make the photoelectric detection circuit. The experimental results show that the photoelectric detection circuit can meet the demodulation requirement and the performance is stable after it is connected with the ultra-weak fiber grating demodulation system.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN253

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