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.


Journal of Electrical and Computer Engineering Innovations (JECEI) welcomes letters to the editor for the post-publication discussions and corrections which allows debate post publication on its site, through the Letters to Editor. Letters pertaining to manuscript published in JECEI should be sent to the editorial office of JECEI within three months of either online publication or before printed publication, except for critiques of original research. Following points are to be considering before sending the letters (comments) to the editor.

[1] Letters that include statements of statistics, facts, research, or theories should include appropriate references, although more than three are discouraged.

[2] Letters that are personal attacks on an author rather than thoughtful criticism of the author’s ideas will not be considered for publication.

[3] Letters can be no more than 300 words in length.

[4] Letter writers should include a statement at the beginning of the letter stating that it is being submitted either for publication or not.

[5] Anonymous letters will not be considered.

[6] Letter writers must include their city and state of residence or work.

[7] Letters will be edited for clarity and length.