# US 2014/0193115 A1 · Method and Apparatus for Optical Waveguide-to-Semiconductor Coupling and Optical Vias for Monolithically Integrated Electronic and Photonic Circuits > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0193115 A1 - Document ID: US20140193115A1 - Status: Published application - Kind: A1 - Application number: 14/152,898 - Filed: 2014-01-10 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: The Regents of the University of Colorado, a body corporate - Applicants: The Regents of the University of Colorado, a body corporate - Inventors: Milos Popovic - Web page: https://patentgrep.com/patent/US20140193115A1 ## CPC - G02B 6/34: utilising prism or grating {(G02B6/293 takes precedence)} - G02B 6/124: Geodesic lenses or integrated gratings - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract An optical coupler has a waveguide coupled to a grating of multiple scattering units, each scattering unit having a first scattering element formed of a shape in a polysilicon gate layer and a second scattering element formed of a shape in a body silicon layer of a metal-oxide-semiconductor (MOS) integrated circuit (IC). The couplers may be used in a system having a coupler on each of a first and second IC, infrared light being formed into a beam passing between the couplers. Vias may be interposed in third ICs between the first and second ICs. The couplers may be configured with nonuniform width of scattering elements to produce Gaussian or focused beams. ## Claims ### Claim 1 An optical coupler comprising: a waveguide coupled to a grating comprising a plurality of scattering units, each scattering unit further comprising a first scattering element formed of a shape in a polysilicon gate layer and a second scattering element formed of a shape in an active layer of a metal-oxide-semiconductor (MOS) integrated circuit, the polysilicon gate layer being formed in a layer also used for gates of MOS transistors of the integrated circuit. ### Claim 2 (depends on 1) The optical coupler of claim 1, the first and second scattering elements in each scattering unit having a respective first and second leading edge toward the waveguide, wherein the first and second leading edges are offset along the in-plane propagation direction from the waveguide to the grating by at least 100 nm. ### Claim 3 (depends on 1) The optical coupler of claim 1 further having a design wavelength of light, the design wavelength of light being an infrared wavelength between 1100 and 1600 nanometers. ### Claim 4 (depends on 2) The optical coupler of claim 2 configured to divert light from the waveguide primarily along a light path directed away from a substrate of the integrated circuit and wherein the repeated scattering units each have the second scattering element closer to the input waveguide than the first scattering element. ### Claim 5 (depends on 2) The optical coupler of claim 2 configured to divert light from the waveguide primarily along a path directed toward a substrate of the integrated circuit, and where a first body scattering element is further from the input waveguide than a first polysilicon element. ### Claim 6 (depends on 2) The optical coupler of claim 2 wherein at least the first and second scattering elements have nonuniform width and spacing, the scattering elements having widths determined to produce a beam having a Gaussian intensity distribution. ### Claim 7 An interlayer optical coupling system comprising: a first integrated circuit having a first coupler, the first coupler comprising a first waveguide coupled to a grating comprising a plurality of scattering units, each scattering unit further comprising at least a first scattering element formed of a shape in a layer selected from an active silicon layer and a polysilicon gate layer of the first integrated circuit, a second integrated circuit having a second coupler, the second coupler comprising a second waveguide coupled to a second grating comprising a plurality of second scattering units, each second scattering unit further comprising at least a second scattering element, the first optical coupler configured to divert light from the first waveguide primarily along a light path directed to the second optical coupler. ### Claim 8 (depends on 7) The system of claim 7 further comprising a via in a third integrated circuit, the third integrated circuit disposed between the first and second integrated circuit, the via comprising a hole, and wherein the light path passes through the via. ### Claim 9 (depends on 7) The system of claim 7 wherein the scattering units of the first coupler further comprise a third scattering element formed of a shape in a different layer than the first scattering element. ### Claim 10 (depends on 10) The system of claim 10, the first or third scattering elements include an active layer, wherein the active layer is a transistor body layer, and the first integrated circuit is a CMOS-SOI integrated circuit. ### Claim 11 (depends on 7) The system of claim 7 wherein the first coupler is configured with first scattering elements having non-uniform width along an in-plane propagation direction in the coupler, the scattering elements having a width distribution determined to focus light of the design wavelength. ### Claim 12 (depends on 7) The system of claim 7 wherein the light path is at least 2 degrees away from propagation direction at right angles relative to a surface of the first integrated circuit. ### Claim 13 (depends on 8) The system of claim 8 further comprising a third and a fourth optical coupler, the third optical coupler being configured to divert light from a third waveguide primarily along a second light path directed to the fourth optical coupler, and wherein the second light path passes through the via. ### Claim 14 (depends on 1) The optical coupler of claim 1 wherein the first and second scattering element are spaced in the plane of the chip by a distance between 100 nanometers (nm) and 2000 nm, and normal to the plane of the chip by between 25 nm to 500 nm. ### Claim 15 A grating coupler comprising: a waveguide coupled to a grating comprising a plurality of scattering units, each scattering unit further comprising a portion of silicon having a first thickness and formed on a first layer of silicon, adjacent a second portion of silicon having a second thickness and formed on a second layer of silicon. ### Claim 16 (depends on 15) The grating coupler of claim 15 formed on a metal-oxide-semiconductor (MOS) integrated circuit, a layer of silicon selected from the first and second layer of silicon being selected from the group consisting of a layer used for gates of MOS transistors of the integrated circuit and a body layer of the integrated circuit. ### Claim 17 (depends on 15) The grating coupler of claim 15, wherein the first and second thickness differ by between 20 nm and 250 nm. ### Claim 18 An optical system comprising: a first integrated circuit having a first coupler, the first coupler comprising a first waveguide coupled to a grating comprising a plurality of scattering units; a second coupler, the second coupler comprising a second waveguide coupled to a grating comprising a plurality of second scattering units; wherein the first coupler is configured as a focusing coupler for producing a focused optical beam having a beam waist between the first and second coupler, the second coupler being aligned to receive the focused optical beam produced by the first coupler. ### Claim 19 (depends on 18) The system in claim 18, further comprising a third integrated circuit having an optical via, wherein the focused optical beam is further configured to pass through the optical via, the via being disposed between the first and the second coupler. ### Claim 20 (depends on 19) The system of claim 19 where a cross-sectional area of the beam waist is between four plus the square root of fifteen and one divided by the quantity four plus the square root of fifteen, times half a product of a distance between the first and second circuits and the wavelength.