Electro-optic amplitude modulation using three-dimensional LiNbO3 waveguide fabricated by TiO2 diffusion

Abstract

An almost single-mode waveguiding layer has been fabricated by thermal diffusion of TiO2 into LiNbO3. The refractive-index change in the layer is 2–3×10−3 for both ne and no, and the propagation loss is 0.7–0.8 dB/cm. The electro-optic coefficients are found to be nearly equal to those of the bulk crystal. An amplitude modulation has been made with a stripe waveguide 10 μm wide and planar electrodes. The half-wave voltage is 17 V and the maximum extinction ratio is 12 dB.