Third-order add-drop filters based on series-coupled microring resonators were fabricated in silicon-rich silicon nitride with accurate dimensional control and negligible sidewall roughness. For the first time, a low 3 dB drop loss is demonstrated with a wide 24 nm free-spectral-range in a high-order microring filter without using the Vernier effect. The spectral response is matched by rigorous numerical simulation, and non-idealities in the drop- and through-port responses are shown to be of design origin and to be correctable.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.