Remotely biasing the electro-optic response of an electric field sensing-detection system using LiNbO₃ asymmetric...

Lithium niobate (LiNbO₃) electro-optic birefringent optical waveguides or electro-optic Mach-Zehnder interferometers have been proposed as electric field sensors in recent years. Electrode-less sensing using LiNbO₃ devices is an active research domain, as they do not perturb the measurands. Asymmetric LiNbO₃ Mach-Zehnder interferometers can be used as electrode-less electric field sensors. However, as an electrode-less sensor cannot be electrically adjusted in the linear region of its electro-optic transfer function, the measurand is imprinted anywhere on such a characteristic. With a view toward achieving a linear response of the sensing-detection process, a simple technique for remotely biasing the electro-optic response, based on two cascaded LiNbO₃ AMZI optical retarders, is described in this paper.