单光纤光栅对温度与应变的同步测量

Strain and temperature simultaneous measurement using a single fiber Bragg grating

提出了一种采用单光纤布拉格光栅(FBG)进行温度与应变同步测量的新颖设计。一根FBG被分成等长的两部分,用环氧胶水涂敷在其中一部分的表面,再套上金属套管,此时可以看成具有不同的布拉格波长的2个FBG,利用它们之间不同的杨氏模量和热膨胀系数,应变和温度能够同步测量。实验结果表明,在2700με和75℃的测量范围内,可以达到约6.1με和1.0℃的应变和温度精确度,误差主要来源于光谱仪分辨率的限制和FBG其中一部分的胶水涂抹不够均匀,通过使用高分辨率的解调仪和提高胶水涂抹工艺可得到更高的测量精确度。

A new scheme for strain and temperature measurement simultaneous is proposed using a single fiber Bragg grating（FBG）.The FBG is divided into two sections which have an equal length,the epoxy glue is daubed on one section,and it is inserted in steel cannula.So the two sections can be regarded as two FBGs with different Bragg wavelengths.Using the differences of their Young′s moduli and coefficients of thermal expansion,both strain and temperature can be measured.in the measurement regions of 2 700 με and 75 ℃,strain resolution and temperature resolution of～6.1 με and ～1.0 ℃ are achieved.These errors are mainly due to the limited resolution of the optical spectrum analyzer and the thickness of the epoxy glue between the fiber and steel cannula is not even.The accuracy and resolution of the sensor can be easily increased by using a FBG demodulator,which has higher resolution,and improving the act of daubing.