Controlling group delay in single and multi-stage slotted ring resonator with fabrication tolerances

Optical delay and corresponding group index of structure composed of slab waveguide coupled with slotted ring resonator are investigated in this paper. Ring resonators have attracted a lot of attention to develop optical delay line which has numerous applications in communication. Properties of these micro ring resonators are highly dependent on waveguide geometry and can be tailored for various applications with minor changes. This paper investigates performance of single and multi stage ring resonators by manipulating geometry and gap between slab and ring waveguide for single mode propagation which may assist to make well informed decisions in the selection process of best-suited ring waveguide for particular application. This investigation is further extended to verify the tolerance of the design in case of fabrication errors with dimension of ±10nm.