Planar Silicon-Polydimethylsiloxane Optofluidic Ring Resonator Sensors

We report an optofluidic ring resonator 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 x 10(4) 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/degrees C. Based on the thermo-optic effect of water, this corresponds to a bulk refractive index (RI) sensitivity of similar to 700 nm per RI unit (RIU), resulting in the RI limit of detection of similar to 1.57 x 10(-6) RIU. The planar architecture combined with an optofluidic design concept holds the promise of high functionality and compactness toward a complete on-chip integrated sensing system.