Birefringent photonic crystal holey fibers based on hexagonal lattice

We analyzed two new constructions of highly birefringent photonic crystal holey fibers based on hexagonal lattice. In the proposed structures, the birefringence is induced either by breaking the hexagonal symmetry in the fiber cladding or in the fiber core, while keeping circular shape of all holes. We calculated modal birefringence vs. wavelength and cut-off wavelengths for all analyzed structures using semi-vectorial plane-wave method. As in the proposed constructions the birefringence is induced by modifying the fill factors of only a few cells with circular holes, we expect that such fibers will be much easier to manufacture than those with rectangular or elliptical shape of the holes.