A method includes etching a silicon layer to form a silicon slab and an upper silicon region over the silicon slab, and implanting the silicon slab and the upper silicon region to form a p-type region, an n-type region, and an intrinsic region between the p-type region and the n-type region. The method further includes etching the p-type region, the n-type region, and the intrinsic region to form a trench. The remaining portions of the upper silicon region form a Multi-Mode Interferometer (MMI) region. An epitaxy process is performed to grow a germanium region in the trench. Electrical connections are made to connect to the p-type region and the n-type region.

Techniques regarding quantum transducers are provided. For example, one or more embodiments described herein can include an apparatus that can include a superconducting microwave resonator having a microstrip architecture that includes a dielectric layer positioned between a superconducting waveguide and a ground plane. The apparatus can also include an optical resonator positioned within the dielectric layer.

An optical device comprises first, second and third elements fabricated on a common substrate. The first element comprises an active waveguide structure supporting a first optical mode, the second element, fabricated on a planarized top surface of the first element, comprises a passive waveguide structure supporting a second optical mode, and the third element, at least partly butt-coupled to the first element, comprises an intermediate waveguide structure, positioned such that a top surface of the intermediate structure underlies a bottom surface of the passive waveguide structure. If the first optical mode differs from the second optical mode by more than a predetermined amount, a tapered waveguide structure in at least one of the second and third elements facilitates efficient adiabatic transformation between the first optical mode and the second optical mode. Mutual alignments of the first, second and third elements are defined using lithographic alignment marks.

A method for fabricating an integrated structure, using a fabrication system having a CMOS line and a photonics line, includes the steps of: in the photonics line, fabricating a first photonics component in a silicon wafer; transferring the wafer from the photonics line to the CMOS line; and in the CMOS line, fabricating a CMOS component in the silicon wafer. Additionally, a monolithic integrated structure includes a silicon wafer with a waveguide and a CMOS component formed therein, wherein the waveguide structure includes a ridge extending away from the upper surface of the silicon wafer. A monolithic integrated structure is also provided which has a photonics component and a CMOS component formed therein, the photonics component including a waveguide having a width of 0.5 μm to 13 μm.

A Mach-Zehnder waveguide modulator. In some embodiments, the Mach-Zehnder waveguide modulator includes a first arm including a first optical waveguide, and a second arm including a second optical waveguide. The first optical waveguide includes a junction, and the Mach-Zehnder waveguide modulator further includes a plurality of electrodes for providing a bias across the junction to enable control of the phase of light travelling through the junction.

Integrated-optics systems are presented in which an active-material stack is disposed on a coupling layer in a first region to collectively define an OA waveguide that supports an optical mode of a light signal. The coupling layer is patterned to define a coupling waveguide and a passive waveguide, which are formed as two abutting, optically coupled segments of the coupling layer. The lateral dimensions of the active-material stack are configured to control the shape and vertical position of the optical mode at any location along the length of the OA waveguide. The active-material stack includes a taper that narrows along its length such that the optical mode is located completely in the coupling waveguide where the coupling waveguide abuts the passive waveguide. In some embodiments, the passive layer is optically coupled with the OA waveguide and a silicon waveguide, thereby enabling light to propagate between them.

Structures for a polarizer and methods of fabricating a structure for a polarizer. A first waveguide core includes a section and a taper connected to the section. A second waveguide core is laterally positioned adjacent to the taper of the first waveguide core. An absorber is connected to the section of the first waveguide core. The absorber is composed of germanium.

A waveguide-coupled Silicon Germanium (SiGe) photodetector. A p-n silicon junction is formed in a silicon substrate by an n-doped silicon region and a p-doped silicon region, a polysilicon rib is formed on the silicon substrate to provide a waveguide core for an optical mode of radiation, and an SiGe pocket is formed in the silicon substrate along a length of the polysilicon rib and contiguous with the p-n silicon junction. An optical mode of radiation, when present, substantially overlaps with the SiGe pocket so as to generate photocarriers in the SiGe pocket. An electric field arising from the p-n silicon junction significantly facilitates a flow of the generated photocarriers through the SiGe pocket. In one example, such photodetectors have been fabricated using a standard CMOS semiconductor process technology without requiring changes to the process flow (i.e., “zero-change CMOS”).

An optical fiber adapter and method of fabricating the same from a wafer including a double silicon-on-insulator layer structure. The optical fiber adapter may include a mode converter, a trench, and a V-groove, the V-groove and the trench operating as passive alignment features for an optical fiber, in the transverse translational and rotational degrees of freedom, and in the longitudinal translational degree of freedom, respectively. The mode converter may include a buried tapered waveguide.

The invention relates to a method for manufacturing a waveguide (2a, 2b) comprising: A supplying of a substrate (1) comprising a stack of a first layer (11) based on a first material on a second layer (12) based on a second material, and at least one sequence successively comprising: An etching of the first material, in such a way as to define at least one pattern (20, 22a) having etching flanks (200, 201), A smoothing annealing assisted by hydrogen in such a way as to smooth the etching flanks (200, 201) of the at least one pattern (20, 22a), A re-epitaxy of the first material on the pattern (20, 22a) based on the first material