基于频移干涉数字混频法的 FBG解调方法  

FBG Demodulation Method Based on Frequency Shift InterferenceDigital Mixing Algorithm

作　　者：魏聪 周次明[1] 陈希 李宇潇[1,2] 刘涵洁 范典 WEI Cong;ZHOU Ci-ming;CHEN Xi;LI Yu-xiao;LIU Han-jie;FAN Dian(National Engineering Laboratory for Fiber Optic Sensor Technology,Wuhan University of Technology,Wuhan 430070,China;School of Information Engineering,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学光纤传感技术国家工程实验室,武汉430070 [2]武汉理工大学信息工程学院,武汉430070

出　　处：《光子学报》2020年第12期34-41,共8页Acta Photonica Sinica

基　　金：国家自然科学基金(No.61775173)。

摘　　要：针对复合频移干涉系统可以通过相位来求解波长的特点,提出了基于频移干涉的数字混频FBG解调方法,并通过理论和实验进行了验证.该算法在解调过程中结合了频移干涉技术光栅准确定位的优势,提高了信号混频阶段本振信号与原始干涉信号频率的一致性,实现了干涉信号相位高精度解调.搭建了基于复合频移干涉结构的FBG传感系统,在仿真和实验测试中通过数字混频法准确解调出了干涉信号初始相位中包含的波长信息,对1.5 nm波长改变量的信号解调误差小于0.26%.同时进行了准动态信号的温度传感实验,具有较好的波长解调效果,在传感监测中具有一定的应用前景.According to the characteristics of the system that the wavelength of the optical signal is calculated by the phase of the modified frequency shift interference system,a digital mixing method based on the modified frequency-shift interference system was proposed,and the FBG wavelength demodulation was experimented.In the demodulation process,the algorithm combines the advantages of the frequency shift interferometric technology to accurately locate the grating,improves the frequency consistency between the local oscillator signal and the original interference signal in the signal mixing stage,and realizes the high-precision phase demodulation of the interference signal.A FBG sensor system was built based on the modified frequency-shift interference structure.In the simulation and experimental test,the wavelength information contained in the initial phase of the interference signal is accurately obtained by digital mixing method.The demodulation error of the 1.5 nm wavelength change signal is less than 0.26%.At the same time,the temperature sensing experiment of quasi dynamic signal is carried out,which has a good effect of wavelength demodulation,and has a certain application prospect in sensor monitoring.

关 键 词：光纤光学 数字混频法 频移干涉 波长解调 光纤布拉格光栅 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]