Characteristics of photonic crystal fibers with different lattices: Realization of constant air percentage by fixing air-filling fraction

The mode properties of solid-core photonic crystal fibers (PCFs) having square, pentagonal, hexagonal, octagonal, nonagonal, decagonal, and dodecagonal lattice formats with uniform air-filling fractions (AFFs) have been evaluated by a full-vector finite-element method using the software COMSOL Multiphysics 4.3. Irrespective of the hole-to-hole spacing for a particular type of lattice, the ratio of air-hole radii of two PCFs having different AFFs is a constant. The ratio of air-hole radii of a pair of PCFs consisting of different lattice types is also found to be constant if the AFF is the same. With dependence on value of AFF used the effect of the order of lattice on the mode area of PCFs exhibit a reversal characteristic while approaching higher order. The effective nonlinear coefficient has been found to be maximized for octagonal PCFs. A reduction in confinement loss to the order of 10(-6) has been observed for higher order PCFs with increased AFF. The variation of the effective area with AFF indicates that it almost reaches saturation for higher ordered structures, but its magnitude is found to decrease with increasing AFF. A flattened dispersion is observed for square PCFs over a wide wavelength range.