Structures for a coupler and methods of forming a structure for a coupler. A structure for a directional coupler may include a first waveguide core having one or more first airgaps and a second waveguide core including one or more second airgaps. The one or more second airgaps are positioned in the second waveguide core adjacent to the one or more first airgaps in the first waveguide core. A structure for an edge coupler is also provided in which the waveguide core of the edge coupler includes one or more airgaps.

Structures for an optical power splitter and methods of forming a structure for an optical power splitter. The structure includes a first waveguide core having a first arm, a second waveguide core including a second arm, and a third waveguide core having a third arm laterally positioned between the first arm and the second arm. The third arm has a longitudinal axis. The first arm is longitudinally offset from the third arm parallel to the longitudinal axis such that the third arm and the first arm are laterally adjacent over a first overlap distance. The second arm is longitudinally offset from the third arm parallel to the longitudinal axis such that the third arm and the second arm are laterally adjacent over a second overlap distance. The first overlap distance is greater than the second overlap distance to provide an overlap offset.

Structures for an optical power splitter and methods of forming a structure for an optical power splitter. The structure includes a first waveguide core having a first arm, a second waveguide core including a second arm, and a third waveguide core having a third arm laterally positioned between the first arm and the second arm. The third arm has a longitudinal axis. The first arm is longitudinally offset from the third arm parallel to the longitudinal axis such that the third arm and the first arm are laterally adjacent over a first overlap distance. The second arm is longitudinally offset from the third arm parallel to the longitudinal axis such that the third arm and the second arm are laterally adjacent over a second overlap distance. The first overlap distance is greater than the second overlap distance to provide an overlap offset.

In a customizable circuit an interconnect matrix is provided that includes only two conductive layers, the matrix defining a first layer of L-shaped conductive lines and a second layer of substantially L-shaped conductive line segments that are connected to electrical components.

A manufacturing method of an optical waveguide device that allows light to propagate through a core formed within a cladding formed on a substrate, the core having a higher refractive index than the cladding, includes: layering a first cladding-material layer for the cladding and a core-material layer for the core sequentially on the substrate; forming the layered core-material layer into the core having a waveguide shape, and removing a first part of the core, the first part being positioned at a portion where a slit is to be formed, to thereby form a gap in the core; layering a second cladding-material layer for the cladding to cover the first cladding-material layer and the core; and removing, by dry-etching, a second part of the first and second cladding-material layers, the second part being positioned at the portion where the slit is to be formed, to thereby form the slit.

A manufacturing method of an optical waveguide device that allows light to propagate through a core formed within a cladding formed on a substrate, the core having a higher refractive index than the cladding, includes: layering a first cladding-material layer for the cladding and a core-material layer for the core sequentially on the substrate; forming the layered core-material layer into the core having a waveguide shape, and removing a first part of the core, the first part being positioned at a portion where a slit is to be formed, to thereby form a gap in the core; layering a second cladding-material layer for the cladding to cover the first cladding-material layer and the core; and removing, by dry-etching, a second part of the first and second cladding-material layers, the second part being positioned at the portion where the slit is to be formed, to thereby form the slit.

Structures for an edge coupler and methods of fabricating a structure for an edge coupler. A waveguide core includes a waveguide core section that has a first notched sidewall, a second notched sidewall, and an end surface connecting the first notched sidewall to the second notched sidewall. Segments are positioned with a spaced arrangement adjacent to the end surface of the waveguide core section, and a slab layer is adjoined to the segments, the first notched sidewall of the waveguide core section, the second notched sidewall of the waveguide core section, and the end surface of the waveguide core section. The segments and the waveguide core section have a first thickness, and the slab layer has a second thickness that is less than the first thickness.

Structures for an edge coupler and methods of fabricating a structure for an edge coupler. A waveguide core includes a waveguide core section that has a first notched sidewall, a second notched sidewall, and an end surface connecting the first notched sidewall to the second notched sidewall. Segments are positioned with a spaced arrangement adjacent to the end surface of the waveguide core section, and a slab layer is adjoined to the segments, the first notched sidewall of the waveguide core section, the second notched sidewall of the waveguide core section, and the end surface of the waveguide core section. The segments and the waveguide core section have a first thickness, and the slab layer has a second thickness that is less than the first thickness.

A system includes a plurality of wafer-scale modules and a plurality of optical fibers. Each wafer-scale module includes an optical backplane and one or more die stacks on the optical backplane. The optical backplane includes a substrate and at least one optical waveguide layer configured to transport and/or manipulate photonic quantum systems (e.g., photons, qubits, qudits, large entangled states, etc.). Each die stack of the one or more die stacks includes a photonic integrated circuit (PIC) die optically coupled to the at least one optical waveguide layer of the optical backplane. The plurality of optical fibers is coupled to the optical backplanes of the plurality of wafer-scale modules to provide inter-module and/or intra-module interconnects for the photonic quantum systems.

A system includes a plurality of wafer-scale modules and a plurality of optical fibers. Each wafer-scale module includes an optical backplane and one or more die stacks on the optical backplane. The optical backplane includes a substrate and at least one optical waveguide layer configured to transport and/or manipulate photonic quantum systems (e.g., photons, qubits, qudits, large entangled states, etc.). Each die stack of the one or more die stacks includes a photonic integrated circuit (PIC) die optically coupled to the at least one optical waveguide layer of the optical backplane. The plurality of optical fibers is coupled to the optical backplanes of the plurality of wafer-scale modules to provide inter-module and/or intra-module interconnects for the photonic quantum systems.