Highly Birefringent Two-Mode Photonic Crystal Fibers With Near-Zero Flattened Dispersion

Through introducing three sizes of holes in cladding, highly birefringent two-mode photonic crystal fibers (PCFs) are proposed. The full-vector finite-element method (FEM) is applied in the calculation of the transverse electric field vector distributions of the two modes, their effective indices, modal birefringence, chromatic dispersion, and confinement losses. The defect holes near the core region are deliberately designed to obtain high birefringence. Furthermore, the structural parameters are carefully selected to flatten chromatic dispersion curve and reduce confinement losses.