光纤光栅链路反射谱强度自适应解调

针对解调仪单通道多光栅反射谱强度差异过大，导致无法有效寻峰或寻峰误差增大的问题，提出了利用不同曝光周期多次曝光解调的方法调整峰值，根据光谱数据直方图来确定寻峰阈值。分析了谱峰峰值对寻峰稳定性的影响，建立了曝光周期、寻峰阈值自适应调整规则，用LabVIEW软件实现了自适应寻峰解调算法。通过实际光纤光栅传感器测试，可完成差异过大反射光谱的自动曝光和寻峰解调处理，在保证寻峰稳定性的前提下，有效提高了谱峰识别数量、解调系统自适应能力和工作可靠性。通过实验发现，谱峰峰值在光强饱和值70%~90%范围内寻峰稳定性最高，寻峰得到的中心波长标准差在0.5 pm以内，稳定性比单次曝光解调提高了50%，程序运行时间在100 ms以内，可以实现快速解调。

Adaptive demodulation of reflection spectrum intensity of fiber grating link

In view of the large difference in the intensity of single channel multi-grating reflection spectrum of demodulator, which leads to the failure of peak-seeking or the increase of peak-seeking error, a method of multiple exposure demodulation in different exposure cycles was proposed to adjust the peak value, and the peak-seeking threshold was determined according to the histogram of the spectral data. The influence of peak value of spectrum on the stability of peak-seeking was analyzed, the adaptive adjustment rules of exposure cycle and peak-seeking threshold were established, and the adaptive peak-seeking demodulation algorithm was realized by LabVIEW software. Through the actual fiber grating sensor test, the automatic exposure and peak-seeking demodulation of the reflection spectrum with large difference could be completed. On the premise of ensuring the peak-seeking stability, the number of spectral peak identification, the adaptive ability of the demodulation system and the working reliability were effectively improved. The experimental results show that the peak stability is the highest when the peak value is in the range of 70%-90% of the saturation intensity. The standard deviation of the center wavelength obtained by peak-seeking is within 0.5 pm, the stability is increased by 50% compared with single exposure demodulation, and the program running time is within 100 ms, which can realize fast demodulation.