High aspect ratio lithium niobate ridge waveguides fabricated by optical grade dicing

We report the development of a quick process for fabricating lithium niobate ridge waveguides with smooth walls, aspect ratios larger than 500 and side-wall verticality of 88 deg. The method is based on optical grade dicing, and allows the fabrication of ridges with a top width of 1 μm and a depth of more than 500 μm. Smart-cut ridge waveguides and strongly confined proton exchanged ridge waveguides are demonstrated. We show that the method enables the fabrication of ridge waveguides with propagation losses as low as 0.5 dB cm-1. A new fabrication process is thus proposed for the fabrication of optical components with enhanced acousto-optic, electro-optic or nonlinear interactions. The high aspect ratios open opportunities towards the development of 3D photonic components in thin films of LiNbO3, and towards hybrid integration of LiNbO3 components.