Highly sensitive silicon photonic temperature sensor based on liquid crystal filled slot waveguide directional coupler

A highly sensitive silicon photonic temperature sensor based on silicon-on-insulator (SOD platform has been proposed and demonstrated. A two-mode nano-slot waveguide device structure cladded with a nematic liquid crystal (LC), E7, was adopted to facilitate strong light-matter interaction and achieve high sensitivity. The fabricated sensor was characterized by measuring the optical transmission spectra at different ambient temperatures. The extracted temperature sensitivities of the El-filled device are 0.810 nm/degrees C around room temperature and 1.619 nm/degrees C near 50 degrees C, which match well with simulation results based on a theoretical analysis. The results obtained represent the highest experimentally demonstrated temperature sensitivity for a silicon-waveguide temperature sensor on SOI platform. The slot waveguide directional coupler device configuration provides submicron one-dimensional spatial resolution and flexible selection in LC materials for designing temperature sensitivity and operational temperature range required by specific applications. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement