啁啾效应对Bragg波长匹配解调精度的影响与消除

Influence of chirp effects on FBG wavelength- matched demodulation precision and it's elimination

介绍了光纤光栅Bragg波长的匹配解调原理,分析了传感光纤光栅和匹配光纤光栅的反射谱相关函数,说明相关函数与光电探测器输出信号具有线性关系。指出基于最大相关原理(光电探测器输出信号极值判断法)的匹配解调只适用于两个光纤光栅具有相同的反射谱型。采用光电探测器输出信号峰值判读时,传感光纤光栅的啁啾效应会引起Bragg波长的解调误差。理论分析和实验研究表明,对光电探测器输出信号进行去卷积运算处理可以消除传感光纤光栅啁啾效应对Bragg波长解调精度的影响。

The principle of wavelength-matched demodulation of fiber Bragg grating (FBG) is introduced. The correlation functions of reflective spectra of sensor fiber grating and wavelength-matched fiber grating are analyzed. The correlation functions are linearity to photoelectric detector output signals. The wavelength-matched demodulation based on maximum correlation, extremum judgment of photodetector output signal, is only available for alike reflective spectra. When the peak value judgment of photodetector output signal is adopted, chirp effects in the FBG sensor lead to demodulation error of Bragg wavelength. Theoretical analysis and experimental investigation show that the deconvolution of photodetector output signal can eliminate Bragg wavelength demodulation error influenced by chirp effects in the FBG sensor.