Refractometric Sensor Based on Silicon Photonic Wires

Integrated optical (IO) refractometric sensors have particularly interesting applications in label-free biosensing and in measuring chemical compositions. A current trend in the research of optical refractive-index sensors focuses on making the sensors compact and highly sensitive [1-3]. We have investigated the refractometric sensing properties of grated silicon photonic wires (GSPW), fabricated using a 248-nm deep UV lithography process [4]. Sharp spectral phenomena of a grated waveguide exhibit strong sensitivity to changes of ambient refractive index while the compact size of the GSPW allows dense integration of several IO sensors on a chip and the use of very small sample volumes, down to the picolitre level.