Single-channel bimodal interferometric sensor using subwavelength structures

A novel configuration of photonic sensors based on a single -channel bimodal interferometer is proposed. The design consists of a subwavelength grating (SWG) periodic structure supporting rivo dispersive TE-like modes that interfere at the output to create fringes in the transmission spectrum Dispersion relations of the bimodal periodic structures have been computed in order to study the sensing performance obtaining a theoretical bulk sensitivity of similar to 130nm/RIU and a surface sensitivity of similar to 6.1nm/nm. Finite-Difference Time Domain (FDTD) analysis has been also carried out in order to confirm the previously obtained sensitivity results, thus showing a perfect agreement between theoretical modelling and simulation. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement