Investigation on parameters affecting the performance of two dimensional photonic crystal based bandpass filter

A two dimensional Photonic Crystal based Bandpass Filter is designed by exploiting coupling between the quasi waveguides and the circular Photonic Crystal Ring Resonator (PCRR). The output efficiency, resonant wavelength and bandwidth of PCBPF are investigated by varying the dielectric constant of the structure. The normalized transmission spectra of circular PCRR are taken using 2D Finite Difference Time Domain method. The Photonic Band Gap is calculated by Plane Wave Expansion method. Close to 100% (Band II) output efficiency is observed over the wavelength range from 1,504 to 1,521 nm and 85% (Band I) is obtained at 1,420 nm through simulation. The full width half maximum bandwidth of these bands is 35 and 20 nm, respectively. Further, the parameters that affect the resonant wavelength, output efficiency and bandwidth of the filter such as size of the reflector, radius of the coupling rods, lattice constant, rod radius and number of rods in the structure are analyzed. The overall size of the proposed filter is 11.4 mu m x 10.2 mu m, which is smaller than the filters already reported in the literature and highly desirable for Photonic Integrated Circuits.