Studies on filtering characteristics of X-shaped photonic crystal waveguide in two-dimensional triangular lattice by microwave model

For the application in wavelength division multiplexing (WDM) system, propagation and filtering characteristics of X-shaped photonic crystal waveguide composed of metallic pillars in two-dimensional triangular lattice were studied in this paper. First, symmetrical X-shaped waveguide and two types of asymmetric X-shaped waveguides were measured to compare their transmission characteristics. Next, three sets of dielectric pillars with different lengths were situated in each output waveguide as cavities. Filtering characteristics were compared to select the most applicable structure as a basic filter component in WDM system.