Composite one-way transmission waveguide based on the curved metal slit and 1D photonic crystal

The one-way devices in optical circuits are the key components just as the diodes in electric circuits, which allow the light going in only one direction. A novel one-way transmission structure is proposed which is a curved waveguide containing a confined photonic crystal. When the waveguide is made of perfect electric conductor, the exact calculation results demonstrate that the device shows excellent one-way properties. The forward transmissivity approaches 100% and the largest transmission ratio exceeds 100.92N, where N is the cell number of the photonic crystal in the structure. When the waveguide is made of real metal, the device also presents excellent one-way transmission properties, which can be confirmed by an approximate calculation as well as by the simulation. In working region, the lowest forward tranmissivity is about 30% and the largest one exceeds 70%. The highest transmission ratio exceeds 104.