Analysis and experimental verification of the HE11 mode in hollow PTFE fibers

This paper studies the fundamental guided mode (HE11) in hollow core polymer fibers. The effect on the effective index of the inside radius, the outside radius and the frequency is studied. Two methods were used to verify this model. Firstly the effective wavelength is measured. The effective indices calculated from the measured effective wavelengths are compared with the model. Secondly the groupdelay is measured. This is then compared to the groupdelay derived from the model. Both approaches are in good agreement with the model.