Proposal for Highly Nonlinear Dispersion-Flattened Octagonal Photonic Crystal Fibers

A highly nonlinear photonic crystal fiber (HNL-PCF) based on an octagonal structure with isosceles triangular-latticed cladding is proposed for the telecommunication window. The finite-difference method with anisotropic perfectly matched boundary layer is used to investigate the guiding properties. It is demonstrated that it is possible to design a simple HNL low-loss dispersion-flattened PCF with a nonlinear coefficient of the order 27 W
^-1
km
^-1
at a 1.55-mum wavelength. According to simulation, ultraflattened dispersion of 0 plusmn 0.5 ps/nm/km is obtained in a 1.46- to 1.66-mum wavelength with low confinement losses less than 0.06 dB/km in the entire band of interest.