Using a full-vector model

we investigate the properties of a kind of high birefringence index guiding photonic crystal fibers.We concentrate on the polarization properties including linear polarization of fundamental modal field

modal birefringence and polarization mode dispersion.Two-fold rotational symmetry was introduced into the fiber structure by creating a regular array of air hole of two different sizes disposed about a pure silica core.The degeneracy of two orthonormal polarized-modes of the fundamental mode was removed.This creates a possibility to attain a modal birefringence of at least one order of magnitude higher than that of conventional high birefringence fibers.A beat length of 0.4067mm is obtained at the wavelength 1540nm.We can obtain much higher birefringence and larger difference of group time delay by choosing different structure parameter of fibers.The numerical results are in very good agreement with the results of experiment.