Investigation on Cavity Based Bandpass Filter Using 2D Photonic Crystal

In this paper, two dimensional Photonic Crystal (2DPC) cavity based Bandpass Filter (BPF) is designed by exploiting coupling between two in-line quasi waveguides and a resonant cavity. The quasi square, tri-quarter square, square, hexagonal and circular cavity based PCBPFs are proposed and investigated. The output efficiency and bandwidth of designed PCBPFs are studied by varying the size of the cavity. The normalized transmission spectra of PCBPF have been studied by using 2D Finite Difference Time Domain (FDTD) method. The Photonic Bandgap (PBG) is calculated by Plane Wave Expansion (PWE) method. The circular cavity based PCBPF gives better performance than others because of its circular resonating modes in the cavity. The number of passbands is increased linearly while increasing the size of the cavity. The total size of the PCBPF chip is about 12 μm × 12 μm.