Channel drop filter based on photonic crystal ring resonator

Photonic crystal ring resonators are promising candidates for realizing all optical filters with acceptable transmission efficiency and quality factor values. In this paper, by putting a hexagon-shaped structure at the middle of on 7 x 7 square cavity we created a ring resonator structure and designed a channel drop filter. The drop wavelength of our filter is at 1550.4 nm, with transmission efficiency and quality factor equal to 94% and 707, respectively. Our structure is composed of dielectric rods immersed in air. Because in this kind of structures the dominant band gap is in TM mode, all of our simulations have been done in TM mode. The total footprint of our filter is 199.4 mu m(2), which makes it suitable for all optical integrated circuits.