Document Type: Original Research Paper


Optoelectronic Research Center, Faculty of Electrical Engineering, Shiraz University of Technology, Shiraz, Fars, Iran


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.


[1] H. Yan, “Integrated optical add-drop multiplexer based on compact parent_submicroring-resonator structure,” Optics Communications, Vol. 289, pp. 53-59, 2013. [

2] D. Zhang, Z. Feng, “A channel drop filter in hetero-woodpile structure”, Optik- International Journal for Light and electron Optics. Vol. 125, Issue. 10, pp. 2422-2425, 2014.

[3] P.P. Yupapin, N. Sarapat, “Novel micro-scale sensors using WGMS within modified add-drop filter circuits”, Microwave and optical technology letters. Vol. 56, Issue. 1, pp. 14-17, 2014.

[4] D.G. Rabus, Integrated ring resonators, The Compendium, Springer-Verlag, Berlin Heidelberg, pp. 4-16, 2007.

[5] L.F. Mollenauer, J.P. Gordon, Soliton in Optical Fibers: Fundamentals and Applications, 1sted. , Academic Press, pp. 30-75, 2006.

[6] Y. Su, F. Liu, Q. Li, “System performance of slow-light buffering and storage in silicon nano-waveguide”, Optical Transmission, Switching, and Subsystems V, Proc. of SPIE. Vol. 6783, pp. 67832-8, 2007.

[7] G.P. Agrawal, Nonlinear ϐiber optics, 4th ed., Academic Press, pp. 150-190, 2007.

[8] I.N. Nawi, H.Hairi, “Analytical Treatment of Parametric Effects in a Ring Resonator”, Procedia Engineering. Vol. 8, pp. 366- 373, 2011.

[9] Y. Wang, H. Zhu, B. Li, “Optical characterization of mechanically tunable micro wire based resonators by changing ring radius and wire diameter”, Opt. commun. Vol. 284, Issue. 13, pp. 3276-3279, 2011.

[10] O. Schwelb, “Transmission group delay and dispersion characteristics of single-ring optical resonators and add/drop filters – A tutorial overview”, J. Lightw. Technol. Vol. 22, Issue. 5, pp. 1380-1394, 2004.