A highly-efficient ridge waveguide includes a base substrate of a single-crystal and a core substrate made of a nonlinear optical medium, the base substrate and the core substrate being directly bonded, and includes a thin film layer formed on a surface of the core substrate on the upper side of a periodically polarization-reversed structure, and becomes a wavelength conversion element. A direct bonding method through thermal diffusion is applied to bonding. The core substrate has a ridge structure formed in a light propagating direction and a reversed structure formed by processing this. A surface of the core substrate is ground and a thin film layer is formed on the ground surface. A core formed by digging a core layer of the core substrate in an unbonded state is provided on an upper surface of an undercladding layer of the base substrate in a bonded state. Two side surfaces of the core are in contact with an air layer.

Technologies pertaining to a chip with a refractive index gradient, including fabrication thereof, are generally described. The refractive index gradient may be formed by creating atomic scale inclusions throughout a thickness of the chip by inducing nanoporosity into the chip, dissociating and diffusing oxygen into the chip, or performing chemical vapor deposition. One or more integrated circuit (IC) components and optical transceiver devices may be provided by mounting, growing, or etching the IC components and optical transceiver devices at a surface of the chip. The optical transceiver devices may be configured to transmit and/or receive an optical communication signal to and/or from at least one IC component or other optical transceiver device via an optical communication path within the thickness of the chip. The optical communication path may include a direction and distance, within the thickness of the chip, based on the refractive index gradient and angle of incidence.

An optical waveguide element includes an optical waveguide which is formed on one surface of a substrate, an incidence part for light to be incident on the optical waveguide or an emission part for emitting light from the optical waveguide which is disposed in an end portion of the substrate, and a dielectric film which is formed on the optical waveguide of at least one of the incidence part and the emission part, and the vicinity thereof. Regarding the dielectric film, dielectric films including a dielectric film formed of a first material having an index of refraction higher than an index of refraction of the substrate and a dielectric film formed of a second material having an index of refraction lower than the index of refraction of the substrate are alternately laminated.

A manufacturing system for fabricating optical waveguides includes a diffusion channel with a plurality of inlets at a first end and an outlet at a second end opposite to the first end and separated from the inlets by a channel length. Each of the plurality of inlets includes a central inlet flowing a first resin into the diffusion channel such that the first resin flows along the channel length of the diffusion channel toward the outlet, and an outer inlet flowing a second resin along a periphery of the first resin. The second resin may have an index of refraction different than the first resin. The diffusion may occur between portions of the first resin and portions of the second resin over the channel length to form a composite resin having a profile with a plurality of indices of refraction in at least one dimension.

A manufacturing system for fabricating optical waveguides includes a diffusion channel with a plurality of inlets at a first end and an outlet at a second end opposite to the first end and separated from the inlets by a channel length. Each of the plurality of inlets includes a central inlet flowing a first resin into the diffusion channel such that the first resin flows along the channel length of the diffusion channel toward the outlet, and an outer inlet flowing a second resin along a periphery of the first resin. The second resin may have an index of refraction different than the first resin. The diffusion may occur between portions of the first resin and portions of the second resin over the channel length to form a composite resin having a profile with a plurality of indices of refraction in at least one dimension.

A highly-efficient ridge waveguide includes a base substrate of a single-crystal and a core substrate made of a nonlinear optical medium, the base substrate and the core substrate being directly bonded, and includes a thin film layer formed on a surface of the core substrate on the upper side of a periodically polarization-reversed structure, and becomes a wavelength conversion element. A direct bonding method through thermal diffusion is applied to bonding. The core substrate has a ridge structure formed in a light propagating direction and a reversed structure formed by processing this. A surface of the core substrate is ground and a thin film layer is formed on the ground surface. A core formed by digging a core layer of the core substrate in an unbonded state is provided on an upper surface of an undercladding layer of the base substrate in a bonded state. Two side surfaces of the core are in contact with an air layer.

Some implementations described herein include a photonics integrated circuit device including a photonics structure. The photonics structure includes a waveguide structure and an optical attenuator structure. In some implementation, the optical attenuator structure is formed on an end region of the waveguide structure and includes a metal material or a doped material. In some implementations, the optical attenuator structure includes a gaussian doping profile within a portion of the waveguide structure. The optical attenuator structure may absorb electromagnetic waves at the end of the waveguide structure with an efficiency that is improved relative to a spiral optical attenuator structure or metal cap optical attenuator structure.

An optical waveguide element includes an optical waveguide which is formed on one surface of a substrate, an incidence part for light to be incident on the optical waveguide or an emission part for emitting light from the optical waveguide which is disposed in an end portion of the substrate, and a dielectric film which is formed on the optical waveguide of at least one of the incidence part and the emission part, and the vicinity thereof. Regarding the dielectric film, dielectric films including a dielectric film formed of a first material having an index of refraction higher than an index of refraction of the substrate and a dielectric film formed of a second material having an index of refraction lower than the index of refraction of the substrate are alternately laminated.

Embodiments of the invention include an electromagnetic waveguide and methods of forming electromagnetic waveguides. In an embodiment, the electromagnetic waveguide may include a first semiconductor fin extending up from a substrate and a second semiconductor fin extending up from the substrate. The fins may be bent towards each other so that a centerline of the first semiconductor fin and a centerline of the second semiconductor fin extend from the substrate at a non-orthogonal angle. Accordingly, a cavity may be defined by the first semiconductor fin, the second semiconductor fin, and a top surface of the substrate. Embodiments of the invention may include a metallic layer and a cladding layer lining the surfaces of the cavity. Additional embodiments may include a core formed in the cavity.

Embodiments of the invention include an electromagnetic waveguide and methods of forming electromagnetic waveguides. In an embodiment, the electromagnetic waveguide may include a first semiconductor fin extending up from a substrate and a second semiconductor fin extending up from the substrate. The fins may be bent towards each other so that a centerline of the first semiconductor fin and a centerline of the second semiconductor fin extend from the substrate at a non-orthogonal angle. Accordingly, a cavity may be defined by the first semiconductor fin, the second semiconductor fin, and a top surface of the substrate. Embodiments of the invention may include a metallic layer and a cladding layer lining the surfaces of the cavity. Additional embodiments may include a core formed in the cavity.