基于PMF-Sagnac环结构的光纤压力传感特性研究

Research on optical fiber pressure sensing characteristics based on PMF-Sagnac loop structure

提出了一种基于熊猫保偏光纤(PMF)-Sagnac环结构的光纤压力传感系统。利用PMF对外界环境的双折射敏感且可进行窄带滤波特性,搭建了压力传感系统,并对该传感系统进行了解调。系统结构简单,成本低,易操作。理论分析表明:当传感单元固定,随着压力的增加,传感系统干涉光的波长漂移呈线性变化。实验验证了传感头分别为1 m和2 m的传感器的压力传感特性。结果显示:随着压力的升高,该传感系统干涉光的波长呈线性变化,线性度分别为0.998和0.995;灵敏度分别为0.258 nm/N和0.133 nm/N;且随着传感光纤长度的增加,透射谱波谷的3 d B带宽不会改变。

A fiber-optic pressure sensing system based on panda polarization-maintaining fiber(PMF)-Sagnac loop structure is proposed.Taking the advantage of sensitivity of birefringence of PMF to external environment and can performs narrow-band filtering,set up pressure sensing system,and demodulation of the sensing system is performed.The proposed system has advantages of simple structure,low cost and easy to operate.Theoretical analysis shows that when the sensing unit is fixed,as the pressure increases,the wavelength drift of interference light of sensing system change linearly.The experiment verifies the characteristics of pressure sensing with the length of the sensor probe is 1 m and 2 m,respectively.The experimental results show that with the increase of pressure,the wavelength of the sensing system changes linearly,the linearity is 0.998 and 0.995,respectively.Meanwhile,the sensitivity is 0.258 nm/N and 0.133 nm/N,respectively.And with the length increasing of sensing fiber,the 3 dB bandwidth of the transmission spectrum trough remain constant.