Abstract: A method for reducing surface recombination in an area next to a mesa in devices containing active and passive sections. This is obtained by growing, by metalorganic vapor phase epitaxy (MOVPE), a thin epitaxial layer of material with larger bandgap than a waveguide material and preferably smaller surface recombination rate than the waveguide material. This thin layer is preferably non-intentionally doped to avoid creating a surface leakage path, thin enough to allow for carrier to diffuse to and thermalize in the waveguide layer and thick enough to prevent carriers to tunnel through it.

Abstract: A method for reducing surface recombination in an area next to a mesa in devices containing active and passive sections. This is obtained by growing, by metalorganic vapor phase epitaxy (MOVPE), a thin epitaxial layer of material with larger bandgap than a waveguide material and preferably smaller surface recombination rate than the waveguide material. This thin layer is preferably non-intentionally doped to avoid creating a surface leakage path, thin enough to allow for carrier to diffuse to and thermalize in the waveguide layer and thick enough to prevent carriers to tunnel through it.

Abstract: A vertical directional coupler fabricated using wafer fusion with a very short coupling length for fabrication of switches, filters and other electro-optic devices. Using the fused vertical coupler, planar waveguides can be fabricated on two different substrates in a three-dimensional structure in which there is vertical coupling between arrays through fused regions. Switches, including crossbar switches based on coupling between independent arrays of waveguides, as well as filters, can be fabricated.