Complete Analysis of the Characteristics of Propagation into Photonic Crystal Fibers, by the Finite Element Method

Using the finite element method, we propose an accurate vector analysis of the lowest electromagnetic modes of photonic crystal fibers. The likeness of their propagation characteristics to those of step index fibers is emphasized. Within the determined limits of a domain of validity, an equivalent step index fiber is defined. In addition, the single-mode broadband behavior of photonic crystal fibers is analyzed. The chromatic dispersion at any wavelength is reliably predicted from the geometric parameters of these fibers. With suitable geometrical parameters, the zero dispersion wavelength can be shifted, for example, toward values close to 1 μm.