Ion-sliced lithium niobate thin films for active photonic devices

We report on sub-micrometer thick LiNbO3 films produced by an improved crystal ion slicing and bonding technique using polymer adhesive benzocyclobutene. The latter enables to reproducibly fabricate defect-free films with an area of several cm2. The method supports also integration of tuning electrodes enabling realization of complex electro-optically active photonic devices on a single chip. Furthermore, the structuring techniques to produce high-index-contrast (Δn ≈ 0.65) single-mode optical waveguides are described. The big potential of the novel LiNbO3 thin films for high-density integrated optics applications is shown on an example of electro-optically tunable microring resonator.