TriPleX-Based Integrated Optical Ring Resonators for Lab-on-a-Chip and Environmental Detection

In this paper, we report experimental results of integrated optics ring resonators (RRs) based on TriPleX waveguide technology. The RRs operate in the near infrared enabling the use of very cost effective VCSELs as a light source. The experimentally obtained response of the ring resontors is in good agreement with theory, while the measured through and drop responses show very low on-chip losses. The chips show good coupling efficiencies to external fibers due to integrated spotsize convertors. The corresponding signal-to-noise ratio enables for measurements of changes in refractive index (RI) smaller than 1 × 10^-6 RIU. The RRs are combined with an 850-nm vertical-cavity surface-emitting laser (VCSEL) as a light source and prototype electronic equipment for signal processing. Several applications are described here, such as RI measurements in fluidic channels, label-free biochemical surface reactions, and gas detection in ambient atmosphere.