针对深井温度变化小, 提出了一种可用于深井温度测量的高灵敏度光纤温度传感器。两根陶瓷插芯从铝管的两端插入构成外腔式光纤法珀干涉仪(EFPI)结构, 用螺钉固定插芯, 再用高强度的环氧树脂密封该结构, 达到防水防尘效果。金属铝和陶瓷插芯具有不同的热膨胀系数, 温度的变化将引起EFPI腔长变化, 采用高灵敏度光纤白光干涉测量技术, 就可以通过测量EFPI腔长获得被测温度。分别在固定温度和不同温度下, 对腔长为 146.5μm的 EFPI光纤温度传感器进行了连续测量。测量结果表明, 高灵敏度EFPI光纤温度传感器的腔长-温度灵敏度为260nm/℃, 温度测量分辨率为0.002℃。

An optical fiber temperature sensor with high sensitivity is presented for the measurement of small temperature change in the deep well. The structure of the sensor is an Extrinsic Fabry-Perot Interferometer (EFPI) with two ceramic ferrules inserted into the center from both ends of the aluminum tube. The ceramic ferrules are fixed with screws, and the high strength epoxy resin is used to seal the structure to achieve the effect of waterproof and dust prevention. Aluminum tube and ceramic cores have different thermal expansion coefficients, and the change of temperature will cause the change of EFPI cavity length. Based on the high-sensitive optical fiber white light interferometry(WLI), the temperature can be obtained by measuring the cavity length of the EFPI. The EFPI optical fiber temperature sensor with the cavity length of 146.5μm is continuously measured in a fixed temperature and different temperature. The results show that the sensitivity of the EFPI optical fiber temperature sensor designed has a temperature sensitivity of 260nm/℃, and a temperature resolution of 0.002℃.