Design of A Lithium Niobate on Insulator Based Waveguide Grating for Refractive Index Sensor

A waveguide grating based on lithium niobate on insulator for refractive index sensor is proposed and simulated. To satisfy the requirement of high accuracy in sensing, the sensor is achieved by a Bragg waveguide grating with uniform period which is divided into sensing window and reference window. Finite-difference time-domain method is used to optimize the design. The sensor offers a sensitivity of 78.6 nm/refractive index unit (RIU) and a minimum detection limit of 10–
²
RIU.