Study of polarization properties of high-birefringence photonic crystal fiber

In this paper, we propose a novel type of photonic crystal fiber with high birefringence. The polarization properties and propagation characteristics of polymer photonic crystal fibres with elliptical air-holes and hexagonal structure are investigated by using the full vectorial plane wave method. The results show that the birefringence of the fibre is induced by asymmetries of the cladding. Moreover, by adjusting the elliptical ratio of cladding, we found out the optimum designing parameters of this fibre with the hole spacing of 1.5 μm in x-axis direction, d/Λ = 0.4, and elliptical ratio of cladding η = 3.0 . This fibre is able to exhibit high birefringence of 10^-2, operating in a single mode regime at an appropriate wavelength range. The range of wavelength is consistent with the communication windows of polymer optical fibres. This conclusion is useful for preparing high birefringence polymer photonic crystal fibers.