Rounded square ring resonator based add drop filter for WDM applications using two dimensional photonic crystals

Abstract

In this paper, two dimensional photonic crystal based Add Drop filter is designed for DWDM applications. The existing work concentrate in Coarse Wavelength Division Multiplexing (CWDM) and few filter design with DWDM with non-uniform channel spacing, and low quality factor. . The proposed Add Drop Filter (ADF) enhances the quality factor using Rounded Square Ring Resonator (RSRR) for ensuring efficient bandwidth in supporting WDM systems. The design consists of bus waveguide, drop waveguide and RSRR with inner quasi-square ring in the square lattice while dielectric constant of the Si rod is 11.68 which are hosted in the air. The line defect was created by removing 4 rods (Quasi ring) in the center of the inner square ring. The line defects in the cavity help to reduce the radiation field components surrounded by the resonator. The proposed design drops the unique wavelength 1636.2 nm from a spectrum. The performance parameters of ADF are investigated using 2DFinite Difference Time Domain (FDTD) algorithm. The proposed ADF drops the narrow bandwidth of 0.7 nm, high quality factor of 2337, dropping efficiency (ON State) of 100 %, which is highly sufficient to support WDM systems for future Photonic Integrated Circuits (PIC). Further, the impact of functional parameters such as transmission efficiency, quality factor, bandwidth are investigated by varying the structural parameters, namely, adjacent rod radius, scatterer rod radius, coupling rod radius, lattice constant, inner rod radius and rod radius. The size of the device is 412.76 µm 2 .