Unique dispersion properties of photonic crystal fibers

In conventional photonic crystal fibers (PCFs), the cladding structure is usually formed by air holes with the same diameter arrayed in a regular triangular lattice. However, in index-guiding PCFs, the periodicity in the cladding region is not essential to confine the guiding light into the high-index core region. In this paper, we report that it is possible to control chromatic dispersion of index-guiding PCFs in wide wavelength range by varying the hole diameter of each air-hole ring along the radius. Using this design principle, a PCF with ultra-low and ultra-flattened dispersion is designed through a full-vector finite element method with anisotropic perfectly matched layers. Effective mode areas and leakage loss properties are also investigated.