基于FFP-TF的分布式光纤光栅动态波长解调方法的研究

Study on Distributed FBG Dynamic Wavelength Measurement Based on FFP-TF

提出一种利用光纤可调谐Fabry-Perot滤波器(FFP-TF)实现分布式光纤光栅动态波长解调的方法,从而实现对一根光纤上多个传感光纤光栅动态应变或振动的分时检测.建立了波长解调数学模型,推导出系统输出电压、输出灵敏度计算公式,得出静态工作点的确定方法.研究了FFP-TF在静态工作点的波长漂移特性,提出加入高频扰动驱动电压的波长锁定方法.基于Labview数据采集平台构建解调系统.实验中通过对系统输出电压进行数字滤波,实现了对频率为100和250 Hz的振动检测.实验结果验证了该解调方法的可行性.

A distributed optical fiber grating dynamic wavelength demodulated method based on fiber Fabry Perot tunable filter（FFP-TF） was proposed,which could measure dynamic strain or vibration of multi-sensing fiber gratings in one optical fiber by time division way.The wavelength demodulated mathematical model was built,the formulas of system output voltage and sensitivity were deduced and the method of finding static operating point was determined.The wavelength drifting characteristic of FFP-TF was discussed when the center wavelength of FFP-TF was set on the static operating point.A wavelength locking method was proposed by introducing a high-frequency driving voltage signal.Based on Labview data collecting unit,the demodulated system was established.In experiment,by digital filtering applied to the system output data,100 Hz and 250 Hz vibration signals were measured.The experiment results proved the feasibility of the demodulated method.