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EP-4177649-B1 - PHOTONIC WAVEGUIDE STRUCTURE

EP4177649B1EP 4177649 B1EP4177649 B1EP 4177649B1EP-4177649-B1

Inventors

  • HOUCK, WILLIAM D.

Dates

Publication Date
20260513
Application Date
20221103

Claims (14)

  1. A photonic waveguide structure (102), comprising: at least four photonic waveguide layers (106-1, 106-2, 106-3, 106-4) disposed in a stack configuration, wherein each photonic waveguide layer comprises an active structure (108) and one or more cladding structures (110), and wherein: a first photonic waveguide layer, of the at least four photonic waveguide layers, includes a first active structure associated with a Kerr coefficient that satisfies a Kerr coefficient threshold, wherein the Kerr coefficient threshold is greater than or equal to 5.0 × 10 -19 meters squared per Watt; and a second photonic waveguide layer, of the at least four photonic waveguide layers, includes a second active structure associated with a propagation loss parameter that satisfies a propagation loss parameter threshold, wherein the propagation loss parameter threshold is less than or equal to 0.55 decibels per centimeter.
  2. The photonic waveguide structure of claim 1, wherein the Kerr coefficient threshold is greater than or equal to 1 × 10 -18 meters squared per Watt.
  3. The photonic waveguide structure of claim 1 or claim 2, wherein the propagation loss parameter threshold is less than or equal to 0.5 decibels per centimeter.
  4. The photonic waveguide structure of any one of the preceding claims, wherein the first active structure and the second active structure are each configured to transmit light with wavelengths from 420 nanometers (nm) to 1600 nm.
  5. The photonic waveguide structure of any one of the preceding claims, wherein respective thicknesses of the first active structure and the second active structure are greater than or equal to 500 nanometers.
  6. The photonic waveguide structure of any one of the preceding claims, wherein the first photonic waveguide layer and the second photonic waveguide layer are formed using one or more sputtering processes.
  7. The photonic waveguide structure of any one of the preceding claims, wherein the at least four photonic waveguide layers are disposed in the stack configuration over a substrate, wherein the second photonic waveguide layer is disposed over the first photonic waveguide layer in the stack configuration, and wherein a third photonic waveguide layer, of the at least four photonic waveguide layers, is disposed over the second photonic waveguide layer in the stack configuration.
  8. An optical device (100), comprising a photonic waveguide structure (102) of claim 1.
  9. The optical device of claim 8 wherein the Kerr coefficient threshold is greater than or equal to 6.2 × 10 -19 meters squared per Watt.
  10. The optical device of claim 8 or claim 9, wherein the propagation loss parameter threshold is less than or equal to 0.1 decibels per centimeter.
  11. The optical device of any one of claims 8-10, wherein the first active structure and the second active structure are each configured to transmit light with wavelengths from 350 nanometers (nm) to 5000 nm.
  12. The optical device of any one of claims 8-11, wherein a material included in the first active structure either is included in the second active structure.
  13. The optical device of any one of claims 8-12, wherein respective thicknesses of the first active structure and the second active structure are greater than or equal to 500 nanometers.
  14. The optical device of any one of claims 9-13, wherein the first photonic waveguide layer and the second photonic waveguide layer are formed using one or more sputtering processes.

Description

BACKGROUND Integrated photonics is a branch of photonics in which waveguides and other photonic devices are fabricated as an integrated structure on a substrate surface. For example, a photonic integrated circuit (PIC) may use semiconductor-grade materials (e.g., silicon, indium phosphide, dielectrics such as silicon dioxide or silicon nitride, and/or the like) as a platform to integrate active and passive photonic circuits with electronic components on a single chip. As a result of integration, complex photonic circuits can process and transmit light (e.g., photons) in similar ways to how electronic integrated circuits process and transmit electrons. US 2020/026000 A1 describes a vertically arranged optical structure including waveguide pairs, dielectric regions, and electrode layers, configured to achieve phase modulation via the Kerr effect or plasma dispersion effect in silicon. SUMMARY The invention is defined in the claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram of an example optical device described herein.Fig. 2 shows a table of some optical characteristics of example materials of an active structure of a photonic waveguide layer described herein. DETAILED DESCRIPTION The following detailed description of example implementations refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. When a PIC is formed, space (e.g., between components) is often limited. For example, components of the PIC are typically created in a single layer on a wafer, which limits a total number of components that can be created on the wafer. As another example, some components in a first layer can comprise materials that are sensitive to high temperatures (e.g., greater than 300 degrees Celsius (C)), and therefore can be damaged when a second layer disposed on the first layer requires a high temperature deposition process. Damage to components of the first layer can affect an optical behavior of the first layer and/or of the PIC. Further, designing a PIC to avoid high temperature processing issues affects an order and/or number of material combinations that can be used in the PIC. Some implementations described herein provide a photonic waveguide structure (e.g., that is a type of a photonic transmission structure) that vertically integrates a plurality of photonic waveguide layers (e.g., at least a threshold number, such as four, photonic waveguide layers disposed in a stack configuration). In this way, the photonic waveguide structure may be capable of both linear optical operations and nonlinear optical operations. For example, the photonic waveguide structure may include a first photonic waveguide layer that includes a first active structure associated with one or more particular nonlinear optical characteristics (e.g., that permit the photonic waveguide structure to perform one or more nonlinear optical operations), and may include a second photonic waveguide layer that includes a second active structure associated with one or more particular linear optical characteristics (e.g., that permit the photonic waveguide structure to perform one or more linear optical operations). Vertical integration of the plurality of photonic waveguide layers in the photonic waveguide structure allows for integration of multiple materials, within the photonic transmission structure, in any order and in multiple photonic waveguide layers. This enables the photonic waveguide structure to provide linear optical operations and nonlinear optical operations that are not possible with a single-layer PIC. In some implementations, various formation techniques may be used to vertically integrate materials in the photonic waveguide structure. For example, one or more sputtering processes may be used to form the plurality of photonic waveguide layers of the photonic waveguide structure. A processing temperature associated with the one or more sputtering processes may be low (e.g., less than or equal to 300 degrees Celsius (°C)), and therefore the one or more sputtering processes are less likely to damage the plurality of photonic waveguide layers than would otherwise be possible using conventional deposition processes with high processing temperatures (e.g., greater than 300°C, and typically greater than 500°C). In this way, a photonic waveguide structure may be formed that could not otherwise be formed using a conventional deposition process (e.g., because of high operating temperatures that would damage at least one of the plurality of photonic waveguide layers in the stack configuration). Fig. 1 is a diagram of an example optical device 100 described herein. An optical device may be, for example, a PIC (e.g., that is capable of one or more linear optical operations and/or one or more nonlinear optical operations) or a similar optical device. The optical device 100 may include a photonic transmission structure, such as a photonic waveguide structure 102 shown in F