Investigating the effects of structural parameters on the optical characteristics of add-drop filters

Effects of the structural parameters on the optical characteristics of an add-drop filter, consisting of two straight waveguides and a micro-ring resonator (MRR), have been investigated. In this research, effects of MRR radius, the width of MRR and waveguide and the gap between MRR and waveguide, on the central wavelength of the signal, free spectral range (FSR) and coupling coefficient have been studied. It is shown that, increasing the radius of MRR would decrease the central wavelength of the input signal; while increasing the width of MRR and waveguide and the gap between MRR and waveguide would increase it. It is found that, by enhancing the gap and width, coupling coefficient would increase at first but after a while it would diminish. It is also concluded that, increasing the radius and width would decrease FSR. The main goal of this research is to study the effects of structural parameters on the functionality of add-drop filters.