Fig. 1. Transmission spectrum test system of fiber air gap F-P etalon

Fig. 2. Transmission spectrum of fiber air gap F-P etalon

Fig. 3. Fitting result of spectral transmission peak based on Lorentz lineshape

Fig. 4. Schematic of skew distribution

Fig. 5. Relationship between FWHM and skewness of F-P etalon transmission peaks

Fig. 6. Skewness and FWHM of F-P etalon transmission spectrum at different beam divergence angles

Fig. 7. Schematic of incident angle deviation

Fig. 8. Change curves of skewness and FWHM of F-P etalon transmission spectrum with the increase of beam incident angle, when beam divergence angle is 1°

Fig. 9. Fitting result of transmission peak based on multi-peak fitting formula