长周期光纤光栅用于材料热膨胀系数的测量

Measurement of Thermal Expansion Coefficient of Material by Long Period Fiber Grating

基于长周期光纤光栅(Long-period fiber grating,LPFG)对应变和温度的敏感特性,用两只LPFG光栅测量材料的热膨胀系数,提出用一只自由状态的LPFG光栅作为实验光栅的温度补偿。实验原理简单,操作方便,克服了传统测量方法对试件本身的要求,且传感信号属于波长解调,不受光强波动及光纤损耗的影响。通过实验获得了对铝板的测量误差约为0.6%,实验结果表明采用LPFG光栅测量材料热膨胀系数的方法是可行的。

An experiment is realized to measure the thermal expansion coefficient by using two long-period-fiber grating based on the theory of the strain and temperature sensitivity characteristic. A method is used to compensate the temperature influence by using another long-period fiber grating at liberty. The principle is simple and the measurement is easy, thus not needing to measure the material＇s dimension. The signal is the modulated wavelength, so it is not reflected by the fluctuation of the light intensity and the fiber loss. The measuring error of the aluminum is about 0. 60%. Results demonstrate that the method is feasible.