New Design of Optical Add-Drop Filter Based on Triangular Lattice Photonic Crystal Ring Resonator

ABSTRACT : In this paper, a new design of add-drop filter based on two-dimensional photonic crystal ring resonator is proposed. The structure is made of a triangular lattice of silicon rods with the refractive index n1=3.4641 which are perforated in air with refractive index n2=1. Resonant modes of the all ring resonator and their corresponding degenerated poles are calculated using the Plane Wave Expansion (PWE) method and the filter’s transmission spectrum is calculated using two-dimensional Finite Difference Time Domain (2D-FDTD) numerical method. Full Width Half Maximum (FWHM) bandwidth of the filter at the output transmission spectrum - from 1.507~1.511?m - is 4nm.The dropping efficiency and quality factor of channel drop filter are 100% and 502.66, respectively. The proposed structure is small and the overall dimension is 10?m×18.5?m which is suitable for photonic integrated circuits.