Lithium niobate optical beam deflectors operating at both electro-optic and thermo-optic modes

Abstract

A novel optical beam deflector based on a Lithium niobate (LN) waveguide is demonstrated, which can operate at both electro-optic and thermo-optic modes. At the electro-optic mode, the microstructured serrated electrodes induce inhomogeneous change in the refraction index of LN waveguide via the Pockels effect when a voltage is applied. The incident beam is thus deflected with the deflected distance changing linearly with the applied voltage. A high deflection speed up to 2.5 GHz is observed experimentally. The optical beam deflector can operate at the thermo-optic mode, where the deflected distance depends on the applied electric power; thus it varies quadratically with the applied voltage. The deflection capacity at the thermo-optic mode is much higher than electro-optic mode, since the deflection distances are respectively 27.19 and 2.53 μm for the thermo-optic and electro-optic modes at a 4 V applied voltage. Therefore, the distinct electro-optic and thermo-optic operating modes enable the LN optical beam deflector to be qualified for various tasks, such as optical scanning, optical modulator.