Multimode Interferometric Biosensor based on the Evanescent-Wave of Si3N4 Rib-Optical Waveguides

Abstract

An integrated-optic, evanescent-wave biosensor utilizing a multimode interferometric waveguide based on a Si3N4 rib-optical waveguide consisting of the Si/SiO2/Si3N4/SiO2 stacked structure was described. It has been confirmed that the very fine changes in the refractive index of an analyte greatly affect the location of interferometric mode patterns and ultimately output optical power, and proved that this principle could be applied to integrated-optic biosensors. The sensitivity for the lengths of the multimode interferers 5380, 5400, and 5420 mu m, respectively was calculated from 6.714 to 7.63 [au/RIU] for the refractive indexrange of 1.33 to 1.35. (C) 2021 The Author(s)