空气隙法布里-珀罗(F-P)标准具是一种常见的光无源器件,其作为滤波器广泛应用于光通信、光电测量和光传感领域。根据经典干涉理论,F-P标准具的光谱为周期出现的洛伦兹峰。但在对F-P标准具透射谱的校准与拟合过程中,发现其透射峰存在左右不对称以及展宽现象,导致使用经典洛伦兹公式的拟合误差较大。通过分析透射峰不对称度和展宽间的关系,并考虑光纤准直器的发散角以及F-P标准具的装配误差因素,提出了一种基于传统F-P干涉理论并融合发散角与入射偏角的多峰叠加拟合公式。使F-P透射谱的拟合方差提高到0.008、重合精度为0.9998, 与基于洛伦兹线型的拟合结果相比提高了近15倍。该研究提供了一种对光纤空气隙F-P标准具透射谱精确拟合的方法,并对其设计以及装配工艺有着重要的指导意义。

Air gap Fabry-Perot (F-P) etalon is a common passive optical device, which, as a filter, has been widely used in optical communications, photoelectric measurement, and optical sensing. Based on the classical multi-beam interference theory, the spectrum of an F-P etalon has periodical Lorentz peaks. However, during the calibration and fitting of the transmission spectrum of a fiber air gap F-P etalon, left-right asymmetry and broadening of the transmission peaks are found. These unexpected phenomena lead to a large fitting error if the classical Lorentz formula is employed. In this study, we firstly analyze the relationship between peak asymmetry and broadening, and then investigate the influence of the divergence angle of a fiber collimator and the assembly error of the etalon. Finally, taking the divergence angle and the incident deflection angle into consideration, we propose a multi-peak superposition fitting formula based on the traditional F-P interference theory. With the new formula, a fitting variance of 0.008 and a coincident accuracy of 0.9998 are achieved for the F-P transmission spectra. Compared with the fitting results of Lorentz lineshape, the fitting accuracy is improved by about 15 times. In conclusion, an accurate fitting method for the transmission spectra of fiber air gap F-P etalons is provided, which has important guiding significance for the design and assembly of the F-P etalons.