Filters Based on Defect Modes by 1D Star Waveguides Defective System

In this paper, we present a theoretical study of the properties of defect modes in one-dimensional defective photonic star waveguides (SWGs). Both symmetrically and asymmetrically stacked defective SWGs are considered in the analysis. The properties of the defect modes are studied through the calculation of the frequency-dependent transmittance. We have also explored the effects of defect length and permittivity, as well as the position of the defect and the number of resonators grafted onto the SWGs on the number of defect modes, their transmission, and their quality factor. The findings demonstrate that geometric defects result in two modes of maximum transmission with a high-quality factor (\({{Q}_{1}} = 358\) and \({{Q}_{2}} = 1550\)). However, when there are both geometric and material defects, the quality factor of the second filter \({{Q}_{2}}\) improved from 1550 to 2203, while the quality factor of the first filter \({{Q}_{1}}\)remains almost unchanged. Moreover, when only material defects are present, two electromagnetic filters with maximum transmission and high-quality factor (\({{Q}_{1}} = 1708\) and \({{Q}_{2}} = 9085\)) can be obtained.