Hybrid square-lattice photonic crystal fiber with high birefringence and negative dispersion

We have proposed a hybrid square-lattice PCF using two different sized air holes and conventional square lattice cladding structure. Based on the plane wave expansion method and finite element method, we numerically investigated it polarization and dispersion properties compared to the conventional square lattice photonic crystal fiber. From the numerical results, it is shown that the proposed structure provides high birefringence and still maintains negative dispersion property. Numerical results show that the birefringence of the hybrid square-lattice PCF reaches 10(-2). The value and slope of the chromatic dispersion are also negative over the C band.