基于长周期光栅滤波的光栅解调系统

基于长周期光栅的边缘滤波特性,设计了一种光纤布拉格光栅的传感解调系统,适用于布拉格光栅的静态和动态解调。系统实现了3.5 nm范围内的线性解调,波长灵敏度为0.092 nm-1,波长分辨率可以达到0.01 nm。振动测量中检测信号稳定,测量频率误差在1%以内。针对长周期光栅对温度和弯曲敏感的问题,采用了适当的温度补偿和封装技术,使长周期光栅的温度漂移系数从112 pm/℃下降到45 pm/℃,显著提高了系统的稳定性。

Filter demodulation of fiber Bragg grating based on long period grating

Based on the edge filter characteristics of long period grating(LPG),an experimental system is built up to achieve static and dynamic demodulation of fiber Bragg grating(FBG).The system can achieve linear dumodulation with a bandwith of 3.5 nm,an wavelength sentitivity of 0.092 nm-1 and an wavelength resolution of 0.01 nm.In vibration measuring,the detected signal is stable,and the frequency error is below 1%.In order to reduce the effect of temperature and strain on the wavelength of LPG,a scheme for the compensation of its drift is designed.Compared with 112 pm/℃ without compensation,the temperature coefficient of LPG is only 45 pm/℃ after compensation.The stability of the system is improved obviously.