Modeling and analysis of multiple ring resonator performance as optical filter

Performance of optical double ring resonator(DRR) and triple ring resonator (TRR) made up of silica-based waveguides, as optical filter is addressed in the article. Vernier principles is adopted in the article and the transmittance of the DRR and TRR is presented in Z-domain. The delay line signal processing approach and Mason's rule have been used to develop the transmittance. The DRR described in the article can produce 300 GHz of free spectral range (FSR) with crosstalk limited within -10dB level and FSR of the TRR achieved is 800 GHz with reduced crosstalk as well as resonance loss remaining within reasonable limits. Group delay and dispersion characteristics around the resonant frequencies is also presented in the article. These wide FSR filters provide ample scope in exploiting the enormous potential in ever expanding field of optical communication using optical frequency division multiplexing (OFDM) or other state of art techniques.