Optical filter in two-dimension photonic crystal waveguide

The factors that affect the properties of the filters in a two-dimensional photonic crystal (2-D PC) waveguide are investigated quantitatively. The waveguide is constructed by omitting one line rods in a perfect 2-D PhC composed of circular dielectric rods located at a square lattice. The 2-D PC filters (2-D PCF) are formed by adding some defect rods in the waveguide. The numerical calculation results show that the reflectivity and transmission of the filter are dependent on the size, dielectric constant and number of defect rods. Moreover, the transmission spectrum of a PCF is also obtained by using fast fourier transform (FFT) method and comb-like curve shape similar to that in the transmission spectrum of Fabry-Perot etalons is found in it.