The model theory was used to analyze the output interference spectrum of single-mode Fabry-Perot interferometer (EFPI) fiber optic sensor in the condition of white light. From this analysis, the normalized function expression of interference spectrum of reflected lights was theoretically derived and the effects on output interference spectrum caused by the FP cavity length and the phase change of the coupling coefficient were analyzed and also compared with the traditional method of geometrical optics. The relationship between the parameters and the output interference is clearly illustrated through computer simulation. The research result provides a high accurate theoretical basis for further research on high precision and high accuracy Fabry-Perot system.
