用于断层测量的温度补偿光纤外腔型法布里-珀罗位移传感器

A FIBRE OPTIC EXTRINSIC FABRY-PEROT INTERFEROMETER WITH TEMPERATURE COMPENSATION FOR FAULT MEASUREMENT

针对光纤EFPI传感器通常尺寸很小,而断层尺寸相对较大,导致光纤EFPI传感器在待测断层处安装不便的情况,提出了一种可用于断层测量的光纤外腔型法布里-珀罗位移传感器。两根陶瓷插芯从陶瓷套管的两端插入构成EFPI结构,通过使用金属内管和金属外管,增大了光纤EFPI位移传感器的尺寸;并且金属外管的两端采用O型圈密封,因此该EFPI位移传感器能够防水防尘。为了消除温度对EFPI位移传感器的影响,两根金属内管采用了不同热膨胀系数的材料在结构上进行温度补偿。在温度连续变化的环境下,对腔长为718.39 m的EFPI位移传感器进行了测量。测量结果显示,经过温度补偿设计后,位移传感器的温度系数由0.14μm/℃下降到了-0.04μm/℃,并呈现过补偿。

Fibre optic EFPI sensor is usually very small in size while the fault size is relatively big, so it is not suitable to be installed at the fault for the fibre optic EFPI. As a result, fibre optic extrinsic Fabry-Perot interferometer for fault measurement, EFPI was present. EFPI structure is formed as two ceramic ferrule inserted into the ceramic casing from the ends. Two ceramic ferrule are respectively fixed on the two metal inner tube, which are inserted into the metal outer tube form the two ends. O-type sealing rings are put at each end of the metal outer tube, so the EFPI displacement sensor is capable of waterproof and dustproof. In order to eliminate the influence of temperature on EFPI displacement sensor, two metal tubes with different thermal expansion coefficient material are chosen for temperature compensation in the structure. In the experiment, EFPI displacement sensor with 718.39μm of the cavity length was measured in a continuous changing temperature situation. The results shows that temperature coefficient of displacement sensor has declined by 0.14 μm/℃ to - 0.04μm/℃ after temperature compensation, and showed a compensation.