Polarization splitter based on dual-core photonic crystal fiber with octagonal lattice

The polarization characteristics of a photonic crystal fiber with octagonal lattice are evaluated by using the finite element method. The coupled-mode theory between two cores is introduced. A novel high extinction ratio and short length polarization splitter based on dual-core octagonal photonic crystal fiber is designed in this paper. Numerical results show that the extinction ratio at the wavelength of 1.55 µm can reach to −175.01 dB, and the bandwidth as the extinction ratio as low as −15 dB is about 82 nm. Besides, a 0.8518-mm-long photonic crystal fiber is better applied to the polarization beam splitter at the communication band of λ = 1.55 µm.