嵌入式微纳光纤环形腔的海水盐度传感研究

Study of Seawater Salinity Sensor Based on Embedded Microfiber Ring Resonator

通过将Loop型谐振腔嵌入在具有正热光系数的MgF2中,设计了海水中温度弱敏感的盐度传感器来实现海水盐度测量。利用COMSOL软件建立海水盐度传感模型,结合Matlab对盐度传感器的特征参量进行数值研究。结果表明:传感器的温度特性依赖于微纳光纤的半径,温度弱敏感的光纤半径随探测波长的减小而减小;盐度灵敏度随镀膜厚度和光纤半径的增大而减小;探测极限随镀膜厚度的增加而增大,随波长的减小而减小。通过优化,传感器盐度灵敏度可达0.025 nm/(mg/mL),探测极限可达到0.15 mg/mL。

A new seawater salinity sensor is designed for salinity measurement by embedding the Loop resonator in MgF2 which has a positive thermo-optic coefficient. The model of seawater salinity sensor is established by COMSOL software and combining with Matlab, and characteristic parameters of the sensor are studied. The results show that the temperature characteristic of embedded ring resonator sensor depends on the microfiber radius, and the size of microfiber for weak temperature dependence decreases with the decrease of wavelength. Higher sensitivity corresponds to smaller coating thickness and smaller microfiber radius. Detection limit increases with the increase of coating thickness and decreases with the decrease of wavelength. By optimizing the parameters of the sensor, sensitivity and detection limit can reach 0.025 nm/（mg/mL） and 0.15 mg/mL, respectively.