高速精确的光纤光栅信号解调方案设计

Design of high speed and accurate fiber bragg grating signal demodulation scheme

为提升光纤光栅的应用效果,为此,设计高速精确的光纤光栅信号解调方案。依据LPFG的光纤光栅信号解调原理,设计两个LPFG双边缘滤波器处理两路反射光,并且利用光电探测器探测光功率结果,以此解调光栅的中心波长;采用光纤干涉仪检测解调频率,对其进行正反扫描,依据光传播时延引起的解调误差和解调频率扫描方向之间的关联,完成解调结果补偿。测试结果显示:该方案具有较好可行性,光谱发生不同程度重叠时,光纤光栅信号的解调结果标准差均小于1.85 pm;光栅波长的解调误差均在-5~5 pm之间;有效降低解调误差,提升光纤光栅解调精度,可靠获取信号中的信息。

In order to improve the application effect of fiber grating,a high-speed and accurate fiber grating signal demodulation scheme is designed.According to the demodulation principle of LPFG fiber grating signal,two LPFG double-edge filters are designed to process the two reflected light,and the photodetector is used to detect the optical power result,so as to demodulate the central wavelength of the grating.The optical fiber interferometer is used to detect the demodulation frequency and perform positive and negative scanning.The demodulation result is compensated according to the correlation between the demodulation error caused by optical propagation delay and the scanning direction of demodulation frequency.The test results show that the scheme has good feasibility.The standard deviation of demodulation results of FBG signals is less than 1.85pm when the spectrum overlaps in different degrees.The demodulation error of grating wavelength is between-5~5pm.Effectively reduce the demodulation error,improve the demodulation accuracy of fiber grating,and obtain the information in the signal reliably.