Design of a high transmission Y-junction in photonic crystal waveguides

A new high transmission Y-junction based on two-dimensional photonic crystal waveguides of triangular lattice is designed. The Y-junction is designed by moving the corner rods of Y-junction into a resonant cavity and placing additional rods between the resonant cavity and the output waveguides. By changing the radius of the additional rods, the transmission coefficient of the Y-junction can be optimized. The coupled mode theory is used to explain the transmission properties. Two-dimensional numerical simulation is performed to verify the Y-junction structure with near-complete transmission.