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Effect of filling high index material on polarization mode dispersion in photonic crystal fibers

Novel highly birefringent photonic bandgap fibers (PBGFs) are obtained by filling high index material in the air holes of total internal reflection birefringent photonic crystal fibers. The effect of filling high-index material on the transmission characteristics has been theoretically investigated. The photonic bandgap has been achieved by using the plane-wave method. Moreover, the polarization mode dispersion (PMD) has been studied by a full-vector finite-element method. Numerical results show that very high PMD with magnitude of order of 10-10 has been respectively acquired, which is much higher than those of the non-filled fibers. Furthermore, strong coupling between surface modes and the fundamental modes has been found in the bandgap of the birefringent PBGFs.