Design of broadband polarization splitter based on partial coupling in square-lattice photonic-crystal fiber

We propose a design for a novel broadband polarization splitter based on an asymmetric dual-core square-lattice photonic-crystal fiber. The fiber is designed such that index-matched coupling between the two cores can be achieved for one polarization state, while only a part of the energy could be coupled for the other polarization state. Numerical results demonstrate that a device length of 5.9 mm shows extinction ratios as low as -20 dB with bandwidths as great as 101 nm.