针对采用传统自组光纤激光器的光纤传感系统存在成本较高和结构复杂等问题, 提出了一种基于商用激光器强反馈的光纤迈克尔逊干涉仪(FMI)传感解调系统。该系统采用商用法布里－珀罗腔型半导体激光器(FP-LD)为光源, 由直流电源直接驱动, 经FMI的反射、干涉后对其形成强反馈; 利用多纵模激光拍频解调技术实现对FMI的传感解调, 将FMI光域干涉光强的变化直接转化为电域拍频包络的变化。研究了不同FMI臂长差时拍频信号随温度的变化过程及传感系统灵敏度。实验结果表明: 当臂长差分别为0.45、0.40 m时, 灵敏度分别为325、358.33 kHz/℃。

Aiming at the problems of high cost and complex structure of optical fiber sensing systems using traditional self organizing fiber lasers, a optical fiber Michelson interferometer(FMI) sensing demodulation system based on the strong feedback of a commercial laser is proposed. The system adopts a commercial Fabry-Perot cavity semiconductor laser diode(FP-LD) as the light source, directly driven by direct-current power supply, and form strong feedback on the FMI after reflection and interference. Multi-longitudinal mode laser beat frequency demodulation technology is used to realize the sensing demodulation of FMI. The change of FMI optical domain interference light intensity is directly converted into the change of electric domain beat frequency envelope. The change process of beat frequency signal with temperature and the sensitivity of sensing system with different FMI arm length difference are studied. The experimental results show that when the arm length difference is 0.45 m and 0.40 m, the sensitivity is 325 kHz/℃ and 358.33 kHz/℃ respectively.