Abstract: An electro-optic device such as a Mach-Zehnder interferometer that includes a lithium niobate substrate having an optical waveguide that is formed in an upper surface of the substrate is described. The device includes a polymer buffer layer formed on the upper surface of the substrate. The polymer may be non-conductive or conductive. An electrode is formed on an upper surface of the buffer layer and is positioned to receive an RF signal that induces an electrical field in the optical waveguide. A conductive charge bleed-off layer may be formed between the buffer layer and the electrode in order to bleed-off pyroelectric charge. A semiconductor charge bleed-off layer may be formed between the substrate and the buffer layer.

Abstract: Integrated devices, comprising an optical waveguide in a substrate, are made by attaching a crystal film to the substrate. Such films can be made by an epitaxial lift-off technique which involves epitaxial growth on an auxiliary substrate, release of a grown single- or multi-layer film from the auxiliary substrate, and transfer of the released film to its intended location where lithographic patterning can be used for the production of devices accurately positioned relative to waveguides. Electrical contacts to devices can take the form of metallic layers which further can serve to secure film edges to the substrate.

Abstract: A planar waveguide comprises a semiconductor substrate having one or more grooves along the surface of the substrate. A plurality of sequences of superlattice layers separated by a spacer layer over the grooved substrate is provided. The number of superlattice periods in each sequence changes from the base of the groove to the surface of the waveguide so as to provide a graded index of refraction in at least a portion of the region above the groove.

Abstract: Optical guidance structure comprising a monomode input guide having a particular direction (De), two monomode output guides having directions (Ds.sub.1, Ds.sub.2) symmetrically inclined with respect to the direction (De) of the input guide and a widened junction zone between the input guide and the output guides. A diffraction grating is located between the input guide and the junction. The grating has a spacing which defines only two diffraction directions of orders differing from zero, respectively +1 and -1. The spacing is chosen so that these two diffraction directions coincide with the directions of the first two output guides.