基于TS-DFT高速光谱解调的FBG温度分布检测

FBG Temperature Distribution Detection Based on TS-DFT High Speed Spectral Demodulation

基于时间拉伸-色散傅里叶变换(time-stretch dispersive Fourier transformation,TS-DFT)技术实现了光纤布拉格光栅反射谱高速解调。解调系统由锁模激光器、环行器、色散补偿光纤、参考光栅、传感光栅以及数据采集和处理模块组成。实验得到了传感光栅在不同温度场下的时域映射光谱,通过与光谱仪测量光谱对比,验证了系统高速光谱解调能力,解调速率为51.2 MHz。结合光谱反演算法得到了沿光栅轴向的温度分布,空间分辨率为200µm,实现了传感光栅高速、高空间分辨率温度传感。

In this paper,high speed demodulation of fiber Bragg grating(FBG)reflectivity spectrum is realized based on time-stretch dispersive Fourier transformation(TS-DFT).The demodulation system consists of mode-locked laser,optical circulator,dispersion compensating fiber,reference FBG,sensing FBG,and data collection and processing module.The time domain mapping spectra of sensing FBG under different temperature fields were obtained in experiments.By comparison with the measured spectra of the optical spectrum analyzer,the high-speed spectral demodulation ability of the system is verified,and the demodulation rate is 51.2 MHz.Combined with the spectral inversion algorithm,the temperature distribution along the axis of sensing FBG is obtained,and the spatial resolution is 200µm.Therefore,temperature sensing with high speed and high spatial resolution is realized.