提高光纤布拉格(Bragg)光栅传感器响应灵敏度是提高光纤布拉格光栅传感系统检测精度的有效途径之一。基于弹性聚合物材料封装和金属波纹管封装对光纤布拉格光栅应力响应的增敏作用,提出了一种新颖的应力响应增敏的高灵敏度光纤布拉格光栅压强传感器模型。推导了该传感器的压强与布拉格波长相对偏移量之间的关系,给出了该传感器压强响应灵敏度系数的解析表达式。表明该传感器布拉格波长相对偏移量和压强之间具有良好的线性关系,同时也指出通过适当选择弹性体的弹性模量、波纹管弹性系数等特性参数,以及它们的尺寸,就可以方便地调整该传感器的压强响应灵敏度系数。该传感器压强响应灵敏度系数实验值高达-4.35×10-9 Pa-1(-6.74 nm/MPa),是裸光纤光栅压强响应灵敏度系数的2197倍,理论值为-4.6×10-9 Pa-1,实验值与理论值吻合得很好。

To enhance the sensitivity of the in-fiber Bragg grating (FBG) sensor is one of the effective ways to improve the resolution of the FBG sensing system. Based on effect of FBG stress sensitivity enhancement by encapsulating the FBG with elastic polymer and a metal bellows, a novel model of high-sensitivity FBG pressure sensor is proposed. The relation between relative shift of Bragg wavelength and the pressure applied on the sensor is derived, and the analytical expression of pressure sensitivity coefficient is also given. It indicates that the relation between the relative shift of Bragg wavelength and applied pressure is linear, and the pressure sensitivity coefficient can be enhanced by properly selecting the parameters of the elastic part and the metal bellows, such as the elastic modulus of the elastic part and the elastic constant of the bellows, and the size of them. The experimental pressure sensitivity coefficient of the sensor is -4.35×10-9 Pa-1 (-6.74 nm/MPa), which is 2197 times of that of the bare FBG, the theoretical value of the sensor is -4.6×10-9 Pa-1, they fit very well.