A new kind of high birefringence photonic crystal fibers with square-lattice cladding

We design a new kind of high birefringence photonic crystal fibers with square-lattice cladding. Through changing the size of only four air holes in the x and y direction respectively, the birefringence is highly increased. It reaches to 1.643×10^-3 when the wavelength is 1.8μm. Based on the finite element method, the mode fields, dispersion and confinement loss of this kind of photonic crystal fibers are all analyzed.