Rashki, Zohreh, and Seyed Javad Seyed Mahdavi. “Novel Design of Optical Channel Drop Filter Based on Photonic Crystal Ring Resonators”. International Academic Journal of Science and Engineering, vol. 1, no. 2, Dec. 2014, pp. 26-35, https://iaiest.com/iaj/index.php/IAJSE/article/view/IAJSE1410020.