A.M. Prabhu and V. Van, “Realization of asymmetric optical filters using asynchronous coupled-microring resonators”, Optics Express, vol. 25, no. 15, pp. 9645, 2007 (web)

M. A. Prabhu and V. Van, “Asymmetric optical filters based on asynchronous coupled microring resonators,” 2007 Conference on Lasers and Electro-Optics – Pacific Rim, Seoul, 2007 (web)