LAUSR

Abstract We have presented a coupling structure of two-dimensional (2D) magneto-optical photonic crystals (MOPCs) with a triangular lattice. The numerical calculation of photonic band structure is performed based on the finite element method. The result shows that photonic band gap of 2D MOPCs with a triangular lattice is much larger than that of 2D MOPCs with a square lattice or a honeycomb lattice under the same applied external magnetic field, i.e., working bandwidth of 2D MOPCs with a triangular lattice is much larger than that of the other two MOPCs. We have studied the coupling effect of one-way edge modes in 2D MOPCs with a triangle lattice, and achieved a unidirectional air waveguide with high-transmission, strong nonreciprocity and extra-broad operation bandwidth. Furthermore, we have qualitatively analyzed waveguide transmission characteristics based on S-parameter method, and illustrated the effective operating bandwidth and the optimum operating frequency for optical waveguide nonreciprocity devices according to different transmission losses in application.