Programmable optical interferometer based on tunable tilted liquid crystal gratings

This study introduces a tunable optical system based on liquid crystal gratings, designed for the infrared (IR) spectrum. The system is designed to be compact, occupying only a few square millimeters, and presents a multilayer configuration featuring a grating between two stacked BK7 glass substrates. An external voltage, applied to the system, activates a secondary pathway configured as a Mach-Zehnder interferometer (MZI) by directing the light through the upper glass layer into two optical channels on the upper system’s surface. Light is then redirected back into the internal waveguide via the top glass layer before finally reaching the system output. The results of the finite-difference time-domain (FDTD) simulations confirm the optical coupling of an incoming out-of-plane light beam into the MZI’s bottom arm via the liquid crystal tilted grating structure. These findings provide a promising foundation for the development of a versatile, compact, and programmable Mach- Zehnder interferometer, all features suitable for applications in optical communication systems and optical biosensing