Advancements in fabricating polymer-based microring resonators by nanoimprint lithography

Polymeric materials for photonic integrated circuits have attracted much interest over the past decades due to their unique properties, including a simple and low-cost fabrication process, low absorption, a broad wavelength range, and a large selection of materials. Polymer-based microring resonators (MRRs) have been widely designed for many applications, from optical communication to medical diagnostics. In medical diagnostics, polymer waveguide MRRs excel as compact and highly sensitive ultrasonic detectors in photoacoustic imaging. In this work, we address the relation of the fabrication parameters to the optical properties of MRRs exhibiting a high quality factor (Q-factor). We use nanoimprint lithography and the UV-curable organic-inorganic material OrmoCore as the waveguide layer. We report our results on loss and coupling characteristics related to structural parameters such as the ring diameter and the residual layer thickness. We achieve low waveguide propagation losses of <0.38 dB/cm and Q-factors of >10^6.