Electro-optical devices and methods for constructing electro-optical devices such as a switch or phase shifter. An electrode layer is deposited on a substrate layer, a waveguide structure is deposited on the electrode layer, a first cladding layer is deposited on the waveguide structure, and the first cladding layer is planarized and bonded to a wafer. The substrate layer is removed and the electrode layer is etched to split the electrode layer into a first electrode separated from a second electrode. A second cladding layer is deposited on the etched electrode layer. The first and second electrodes may be composed of a material with a large dielectric constant, or they may be composed of a material with a large electron mobility. The device may exhibit a sandwich waveguide architecture where an electro-optic layer is disposed between two strip waveguides.

Embodiments of the disclosure provide a waveguide-confining layer, a photonic integrated circuit (PIC) die with embodiments of a waveguide-confining layer, and methods to form the same. The waveguide-confining layer may include an oxide layer over a buried insulator layer, a silicon-based optical confinement structure embedded within or positioned on the oxide layer, and first and second blocking layers over the oxide layer and separated from each other by a horizontal slot. The first and second blocking layers include a metal or an oxide. A gain medium is positioned on the oxide layer and within the horizontal slot between the first and second blocking layers, and has a lower refractive index than each of the first and second blocking layers. The gain medium is vertically aligned with the silicon-based optical confinement structure, and a portion of the oxide layer separates the gain medium from the silicon-based optical confinement structure.

Structures for a wavelength-division multiplexing filter and methods of forming a structure for a wavelength-division multiplexing filter. The structure includes a first slab having a first perimeter, a first waveguide core coupled to the first slab, and a plurality of second waveguide cores coupled to the first slab. A second slab is positioned to overlap with the first slab. The second slab includes a second perimeter and openings that are distributed inside the second perimeter. The openings of the second slab penetrate through the second slab.

Structures for a wavelength-division multiplexing filter and methods of forming a structure for a wavelength-division multiplexing filter. The structure includes a first slab having a first perimeter, a first waveguide core coupled to the first slab, and a plurality of second waveguide cores coupled to the first slab. A second slab is positioned to overlap with the first slab. The second slab includes a second perimeter and openings that are distributed inside the second perimeter. The openings of the second slab penetrate through the second slab.

A germanium waveguide is formed from a P-type silicon substrate that is coated with a heavily-doped N-type germanium layer and a first N-type doped silicon layer. Trenches are etched into the silicon substrate to form a stack of a substrate strip, a germanium strip, and a first silicon strip. This structure is then coated with a silicon nitride layer.

A photonic integrated circuit includes a substrate, an interconnection layer, and a plurality of silicon waveguides. The interconnection layer is over the substrate. The interconnection layer includes a seal ring structure and an interconnection structure surrounded by the seal ring structure. The seal ring structure has at least one recess from a top view. The recess concaves towards the interconnection structure. The silicon waveguides are embedded in the substrate.

An optical cavity includes a ring defining an internal boundary and an external boundary, at least one of which is periodically modulated to define a gear-shaped configuration including a plurality of teeth, thereby enabling a plurality of slow-light modes. At least one physical defect may be defined within the periodically modulated internal boundary and/or external boundary to thereby enable at least one localized mode. At least one waveguide is coupled to the ring.

End-face coupling structures within an electrical backend are provided via photonic integrated circuit (PIC), comprising: a first plurality of spacer layers; a second plurality of etch-stop layers, wherein each etch-stop layer of the second plurality of etch-stop layers is located between two spacer layers of the first plurality of spacer layers; and an optical coupler comprising a plurality of waveguides arranged as a waveguide array configured to receive an optical signal in a direction of travel, wherein each waveguide of the plurality of waveguides is located at a layer interface defined between an etch-stop layer and a spacer layer. Portions of the PIC can be formed by depositing layers of spacer and etch-stop materials in which cavities are formed to define the waveguides when the waveguide material is deposited or interconnects when a metal is deposited therein.

A photonic integrated circuit chip includes vertical grating couplers defined in a first layer. Second insulating layers overlie the vertical grating coupler and an interconnection structure with metal levels is embedded in the second insulating layers. A cavity extends in depth through the second insulating layers all the way to an intermediate level between the couplers and the metal level closest to the couplers. The cavity has lateral dimensions such that the cavity is capable of receiving a block for holding an array of optical fibers intended to be optically coupled to the couplers.

A cavity substrate may have a directional optoelectronic transmission channel. The cavity substrate includes a support frame, a first dielectric layer on a first surface of the support frame, and a second dielectric layer on a second surface of the support frame. The support frame, the first dielectric layer and the second dielectric layer constitute a closed cavity having an opening on one side in the length direction of the substrate, a first circuit layer is arranged on the inner surface of the first dielectric layer facing the cavity, an electrode connected with an optical communication device is arranged on the first circuit layer, the electrode is electrically conducted with the first circuit layer, a second circuit layer is arranged on the outer surfaces of the first dielectric layer and the second dielectric layer, and the first circuit layer and the second circuit layer are communicated through a via column.