基于3×3耦合器的光纤光栅温度传感器解调系统

Demodulation System of Fiber Bragg Grating Temperature Sensors Based on 3×3 Fiber Coupler

针对光纤光栅的温度应变交叉敏感问题,提出了一种管式光纤光栅温度传感器,使用外径8mm、内径6mm、长9cm的不锈钢管作为材料,制作了只对温度敏感的光纤光栅传感器,实验表明,传感器呈现良好的温度线性,温度灵敏系数为9.72pm/℃,稳定性好。在此基础上,采用了基于3×3耦合器的干涉型光纤光栅温度解调方案,详细的推导了信号解调过程,经过实验验证了解调方法的可行性及稳定性,实验结果表明,温度测量系统在40℃～100℃的测量范围内温度测量误差小于0.1℃,达到了工程应用的要求。

In view of the cross-sensitivity of temperature and strain of fiber Bragg grating (FBG),a tubular fiber Bragg grating temperature sensor is proposed. In this paper,the stainless-steel pipes with 8 mm outer diameter,6mm inner diameter and 9cm length are used as materials to fabricate temperature-sensitive fiber grating sensors. The experimental results show that the sensor has a good temperature linearity and temperature sensitivity coefficient of 9.72pm/℃ and has a good stability. On this basis,an interferometric fiber grating temperature demodulation scheme which based on 3 × 3 coupler is adopted;and the demodulation process is deduced in detail. The feasibility and stability of the method are verified through experiments. The experimental results show that the temperature measurement error of the system is less than 0.1℃ in the range of 40℃ to 100℃,which meets the requirement of Engineering application.