两光纤布拉格光栅(FBG)的光谱失配会使其构成的光纤法布里珀罗(FFP)传感系统的干涉条纹可见度降低，从而影响探测性能。基于弱反射率FBG反射谱的高斯波形近似，推导了光谱失配引起的可见度变化表示式。实验测量了干涉型FFP传感系统的可见度曲线，对理论分析进行了验证。研究表明，反射谱旁瓣对光谱失配引起的可见度变化有重要影响。从光谱匹配的角度，采用高斯切趾光栅的FFP传感系统优于普通均匀光栅的系统。

Spectral mismatch between spectral profiles of two fiber Bragg gratings (FBGs) can deteriorate the fringe visibility of the constructed fiber Fabry-Perot (FFP) sensor system. Under the approximation of Gaussian profiles to reflection spectra of weak fiber Bragg gratings, the expression describing fringe visibility variations induced by spectral mismatch is deduced. The curve of fringe visibility is measured in an interferometric FFP sensor system, which is in good agreement with the theoretical analysis. The investigation indicates that, side lobes in reflection spectra of FBGs have a big influence upon visibility variations caused by spectral mismatch. And from the spectral match point of view, the FFP sensor system based on Gaussian apodized gratings is superior compared with that on normal uniform gratings.