同时测量海水盐度温度的微光纤耦合器研究

Study on Microfiber Coupler for Simultaneous Measurement of Seawater Salinity and Temperature

为实现同时测量海水的盐度温度,研制了2×2四端口微光纤耦合器型传感器。耦合器锥形过渡区激发的偶超模与奇超模在S均匀腰区传输时将逐渐累积相位差,产生干涉光谱。研究表明:波谷位置分别随着海水盐度、温度的改变而移动,得到了2个波谷的盐度灵敏度为1418.00和1600.00 pm/‰,温度灵敏度为-745.00和-778.00 pm/℃,建立了灵敏度矩阵。通过追踪这2个波谷位置,结合灵敏度矩阵,可实现对任意待测样品盐度、温度的同时测量,与盐度计、热电偶温度计实测数据的对比表明,此传感器具有很好的准确度。该盐度、温度双参数测量传感装置具有小尺寸、易制作和高灵敏度等优势,本研究为海洋环境及海洋动力现象的研究提供了一种新型的光学探测方法。

A 2×2 microfiber coupler is developed to realize the simultaneous measurement of seawater salinity and temperature.The even and odd supermode,which are excited in the conical transition region of coupler,show different effective refractive index,and the phase difference between them will be gradually accumulated when transmitting in the uniform waist region,which finally generate interfe-rence spectra.The result shows that the positions of the interference dip linearly shift with the change of salinity and temperature,respectively.By tracking the positions of two dips,salinity sensitivity of 1418.00 and 1600.00 pm/‰,as well as temperature sensitivity of-745.00,-778.00 pm/℃are obtained,respectively.A sensitivity matrix is further established to simultaneously measure seawater salinity and temperature.The measurements of this sensor are consistent with those of salinometer and thermocouple thermometer,which indicates that the sensor has good accuracy and reliability.The sensor demonstrated here shows advantages of small size,easy fabrication,high precision,and high sensitivity,which provide a potential optical detection method for marine environment and ocean`dynamical phenomena research.