提出并设计了一种基于液体腔结构的全光纤Fabry-Perot (F-P)传感器,对F-P传感器原理进行了研究。采用内径为0.3 mm的玻璃毛细管作为套管,将两根SMF-28单模光纤插入套管构成F-P结构,并通过在腔内填充液体进一步提高传感器的灵敏度。实验中,以空气及纯净水作为腔内介质,分别制备了光纤端面距离为119 μm和123 μm,反射谱周期以及条纹对比度分别为15.15 nm、14.13 nm和11.17 dBm、11.83 dBm。实验中对所制备的两种F-P传感器分别进行了温度特性的测试,在20 ℃的范围内,每间隔2 ℃对反射光谱进行采集。对于空气腔结构F-P传感器,随着温度逐渐升高,波长发生红移,特征波谷波长漂移量为2.39 nm,温度灵敏度为121 pm/℃,线性度为0.94,最大功率漂移为1.17 dBm；对于液体腔结构F-P传感器,随着温度逐渐升高,波长发生红移,特征波谷漂移量为5.31 nm,温度灵敏度为243 pm/℃,线性度为0.98,最大功率漂移量为4.07 dBm。
An all-fiber Fabry-Perot (F-P) sensor based on liquid cavity structure was proposed and designed. The principle of F-P sensor was researched. A glass capillary tube with an internal diameter of 0.3mm was used as the casing pipe,two SMF-28 single-mode optical fibers were inserted into the glass capillary to form the F-P structure,and the sensitivity of the sensor was further improved by filling the cavity with liquid. In the experiment,air and purified water were used as the medium in the cavity to prepare the fiber end face distance of 119 μm and 123 μm,and the reflection spectrum period and fringe contrast were respectively 15.15 nm,14.13 nm,11.17 dBm and 11.83 dBm. Two prepared F-P sensor’s temperature characteristic were tested respectively in the experiment,in the range of 20℃,2℃ per interval of reflection spectrum were collected. For air F-P cavity structure sensor,as the temperature increased,the wavelength redshift,characteristics trough wavelength drift was 2.39 nm,the temperature sensitivity was 121 pm/℃,linearity fitting was 0.94,the maximum intensity drift was 1.17 dBm;For liquid cavity F-P structure sensor,as the temperature increased,wavelength redshift,characteristics trough wavelength drift was 5.31 nm,the temperature sensitivity was 243 pm/℃,linearity fitting was 0.98,the maximum intensity drift was 4.07 dB.