Optical waveguide resonator for one-port refractive index sensing

We report an optical waveguide sensor using ring resonator. A refractive index sensor using resonator with vertical light input will be described. A grating coupler is used to couple the light beam to waveguide and output the light beam. The device has diameter of 40 μm with 500 nm wide waveguide, and fabricated in silicon on insulator (SOI). Experiments show that it has 313 nm/RIU sensitivity and detection limit of 1.5×10^-3 RIU for changes in the refractive index of the sample.