Planar Silicon-Polydimethylsiloxane optofluidic ring resonator sensors

We report an optofluidic ring resonator (ORR) sensor based on liquid-core hybrid silicon-polymer waveguides. The device features a planar layout that combines optical and fluidic functions on the same platform. A high quality factor of 1.44 ×104 is achieved. The device resonant wavelength shift has been measured as a function of the water-core temperature, obtaining a temperature sensitivity of 0.0633 nm/°C. Based on the thermo-optic effect of water, this corresponds to a bulk refractive index (RI) sensitivity of about 700nm per refractive index unit (RIU), resulting in the RI limit of detection of about 1.57×10-6 RIU. The planar architecture combined with an optofluidic design concept holds the promise of high functionality and compactness towards a complete on-chip integrated sensing system.