A generalized approach for determination of transmittance (transfer function) in Z-domain of optical waveguide based ring resonator is introduced in the present article. Delay line signal processing technique, developed by a few previous researchers, is used to develop the signal flow graph of different ring resonator architectures, and a rule, already established by a previous investigator, is implemented to determine its overall transmittance. Frequency responses of three different ring resonator architectures are presented in the article. The parameters describing the performance of optical filter can be directly estimated from the frequency response plot. The simulated results of single and double ring architectures are compared with those of previously published results. A waveguide based triple ring resonator architecture is proposed, and its frequency response analysis is carried out in the article. (c) 2006 Published by Elsevier B.V.