Simultaneous measurement of temperature and concentration of sugar solution based on hybrid fiber grating sensor

In order to accurately measure temperature and concentration of sugar solution at the same time,we presented a hybrid fiber grating sensor. Firstly,based on mode coupling theory,hybrid fiber gratings were formed using fiber Bragg grating and long-period fiber grating,which could realize dual-parameters measurement. In this hybrid fiber grating,FBG response to temperature measurement,while LPFG response to simulataneous measurement of sugar solution concentration and temperature. Then,in two linear refractive index ranges,that is,from 1. 33 to 1. 42 and from 1. 42 to 1. 44,we calibrated correlation coefficient of temperature and sugar concentration. Finally,two sensitivity coefficient matrixes were constituted to discuss the method of measuring temperature and sugar solution concentration simultaneously. Experimental results indicate that the measuring sensitivity of temperature reaches 117. 9 pm / K,and sugar solution concentration reaches – 213. 5pm / RIU. Therefore,the modular fiber grating sensor has high sensitivity property as the photochemical sensor.