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.

We report a waveguide optical sensor using wire waveguide array. A grating coupler is used to couple waveguide modes with input and output light beam. A resonant cavity is formed by Bragg grating or ring waveguide to enhance the sensitivity. A high reflectivity is also realized by high-order modes at the abrupt waveguide end in the array waveguide structure.