Highly birefringent elliptical-hole photonic crystal fiber with squeezed hexagonal lattice

We propose a novel polarization-maintaining index-guiding photonic crystal fiber (PCF). It is composed of a solid silica core and a cladding with squeezed-hexagonal-lattice elliptical air holes. Using a full-vector finite-element method, we study the modal birefringence of the fundamental modes in such PCFs. Numerical result shows that very high modal birefringence with a magnitude of the order of 10(-2) around 1550 nm has been obtained. Furthermore, large normal dispersion appears over a wide range of wavelengths in both orthogonal polarizations.