设计了基于双光纤布拉格光栅(FBG)的高灵敏度应变光纤传感实验教学系统. 两只具有不同反射中心波长(1 546.209 nm和1 541.713 nm)的FBG串联熔接后，分别黏贴于等强度悬臂梁的上表面与下表面. 通过测量两只FBG的反射中心波长差值与等强度悬臂梁应变量的关系，实现对应变量的传感测量. 仿真结果显示，双FBG应变传感的灵敏度为单FBG应变传感的2倍，且具有温度自补偿特性. 实验结果验证了仿真分析的结论，测得双FBG应变传感的灵敏度为2.10 pm/με，且传感测量准确性不受环境温度变化影响.

A high sensitivity dual-fiber-Bragg-gratings (FBGs) based strain sensing system is proposed. It consists of two FBGs with different center reflection wavelengths (1546.209 nm and 1541.716 nm), which are respectively sticked on the upper surface and lower surface of a triangle cantilever beam of constant bending rigidity. Through measuring the relationship between the two FBG’s center reflection wavelength difference and the strain of the triangle cantilever beam, the strain fiber sensing can be achieved. The simulations have demonstrated that the sensitivity of the dual-FBGs based strain sensing system is two times of that of the single-FBG based one, and the temperature influence can be compensated automatically in the proposed sensing system. The experimental data verify the conclusion draw from the simulations, show a strain sensing sensitivity of 2.10 pm/με, and demonstrate that the measurement accuracy is safe from the temperature variation induced influence.