This tutorial describes the transmission, group delay time and quadratic dispersion properties of the four basic building blocs of optical filters built using ring resonators. These building blocs are single-ring resonators in either two-port (all-pass) or four-port (add/drop filter) configuration. The effect of waveguide and coupler loss is included throughout. Explicit expressions to compute the complex amplitude of the circulating wave in the ring, the Q factor, the finesse and the insertion loss are also given. Attention is drawn to the similarities between the ring resonator the Fabry-Pérot resonator and the Gires-Tournois interferometer. Material properties and fabrication technology are not reviewed.
© 2004 IEEE
Otto Schwelb, "Transmission, Group Delay, and Dispersion in Single-Ring Optical Resonators and Add/Drop Filters - A Tutorial Overview," J. Lightwave Technol. 22, 1380- (2004)