A Study on the Design of Integrated-Optic Biosensor based on the Power Coupling of Two Modes utilizing Si<inf>3</inf>N<inf>4</inf>Rib-Optical Waveguides

Abstract

We proposed an integrated-optical biosensor configuration that operates at a wavelength of 0.63 μm based on the evanescent-wave and lateral two-mode power coupling of Si3N4 rib-optical waveguides formed on a Si/SiO2/Si3N4/SiO2 multilayer thin films. The coupling between the two propagating modes in the sensing region produces a periodically repeated optical power exchange along the propagation. The light power was steered from one output channel to the other caused by the change of the cladding layer (bio-material) refractive index, which affect the effective refractive index (phase-shift) of two modes through evanescent-waves. The sensitivity 1223 [au/RIU] was evaluated for the two-mode region of the width and length of 4 μm and 3841.46 μm, corresponding to the refractive index range 1.36-1.43. © 2020 IEEE.