Shahid Rajaee Teacher Training University Journal of Electrical and Computer Engineering Innovations (JECEI) 2322-3952 3 1 2015 01 01 FSR Decrement and Coupling Coefficient Increment in Add-Drop Filters 13 16 339 10.22061/jecei.2015.339 EN E. Rafiee Optoelectronic Research Center, Faculty of Electrical Engineering, Shiraz University of Technology, Shiraz, Fars, Iran F. Emami Optoelectronic Research Center, Faculty of Electrical Engineering, Shiraz University of Technology, Shiraz, Fars, Iran Journal Article 2015 02 15 In this paper, 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 free spectral range (FSR) and coupling coefficient have been studied. It is found thatby enhancing the gap and width, coupling coefficient would be increased at first but after a while it would be decreased. It is also shown that, increasing the radius and width would decrease FSR. The main goal of this research is to decrease FSR and increase the coupling coefficient of add-drop filters, which are widely used in communication applications. https://jecei.sru.ac.ir/article_339_00f2a86ab6c0b99cc4670c1f5ca917e1.pdf