FBG温度传感器探头的封装设计方案

The encapsulation scheme of temperature sensor based on FBG

提出了一种基于FBG(布拉格光纤光栅)温度传感器封装的新设计方案。一个密闭的容器被活塞分成两部分,一部分充满水银,另一部分抽成真空,两个完全一样的布拉格光纤光栅分别安装在活塞两边。当温度发生变化时,通过水银的热胀冷缩推动活塞移动,把温度的变化通过水银热胀冷缩转换成对光纤光栅的拉力和压力。而光纤光栅和金属外壳本身的热胀冷缩对两段布拉格光栅的影响是相同的,基本上可以相互抵消,因此,消除了温度和应力交叉敏感的问题。另外,理论分析表明该布拉格光纤光栅传感头的温度灵敏度可以达到2.83×10-4/℃。

The encapsulation design based on the Fiber Bragg Gratings sensors has been proposed.The kind of sensors is made of two FBGs with the same central wavelength,one of which is in the hermetic container filled fully with the mercury;the other is in the hermetic container with vacuum.When the temperature of mercury varies,the expansibility of the mercury on piston would convert the temperature variety into the pull and the extrusion on FBGs.Meanwhile the influences on the FBGs from the expansibility of FBGs and metal are same and could offset on the whole,which eliminate the cross sensitivity issue of the temperature and the stress.In addition,on theory the temperature sensitivity of the FBGs probe could arrive 2.83×10-4/℃.