# US 11,441,903 B2 · Ring waveguide based integrated photonics optical gyroscope with gain tuning for enhanced performance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,903 B2 - Document ID: US11441903B2 - Status: Granted - Kind: B2 - Application number: 17/373,298 - Filed: 2021-07-12 - Published: 2021-11-04 - Granted: 2022-09-13 - Earliest claimed: 2019-11-27 - Assignees: Anello Photonics, Inc. - Applicants: Anello Photonics, Inc. - Inventors: Mario Paniccia - Web page: https://patentgrep.com/patent/US11441903B2 ## CPC - G01C 19/66: Ring laser gyrometers - G01C 19/727: {using a passive ring resonator} - G01C 19/721: {Details, e.g. optical or electronical details} - G02B 6/126: using polarisation effects {(G02B6/1226 takes precedence)} - G02B 6/2726: {in or on light guides, e.g. polarisation means assembled in a light guide} - G02B 6/29338: {Loop resonators} - G02B 2006/12138: {Sensor} - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first straight waveguide to receive incoming light and to output outgoing light to be coupled to a photodetector to provide an optical signal for rotational sensing. The gyroscope comprises a first microresonator ring proximate to the first straight waveguide. Light evanescently couples from the first straight waveguide to the first microresonator ring and experiences propagation loss while circulating as a guided beam within the first microresonator ring. The guided beam evanescently couples back from the first microresonator ring to the first straight waveguide to provide the optical signal for rotational sensing after optical gain is imparted to guided beam to counter the propagation loss. In a coupled-ring configurations, the first microresonator ring acts as a loss ring, and optical gain is imparted to a second microresonator ring which acts as a gain ring. ## Claims ### Claim 1 An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform, comprising: a first straight waveguide to receive incoming light from one or more light sources and to output outgoing light to be coupled to a photodetector to provide an optical signal for rotational sensing; and a first microresonator ring proximate to a portion of the first straight waveguide, wherein light evanescently couples from the portion of the first straight waveguide to the first microresonator ring and experiences propagation loss while circulating as a guided beam within the first microresonator ring, wherein the guided beam evanescently couples back from the first microresonator ring to the portion of the first straight waveguide to provide the optical signal for rotational sensing after optical gain is imparted to the guided beam in at least a portion of the first microresonator ring to counter the propagation loss, wherein a first portion of the first microresonator ring and a second portion of the first microresonator ring are fabricated on different physical layers vertically stacked on top of each other, and wherein light couples evanescently between the two physical layers that are vertically separated. ### Claim 2 (depends on 1) The integrated photonics optical gyroscope of claim 1, wherein the one or more light sources are at one end of the first straight waveguide or at both ends of the first straight waveguide. ### Claim 3 (depends on 2) The integrated photonics optical gyroscope of claim 2, wherein a pump light of suitable wavelength is coupled to the first microresonator ring to induce Stimulated Raman Scattering (SRS) to provide the optical gain. ### Claim 4 (depends on 2) The integrated photonics optical gyroscope of claim 2, wherein a pump light of suitable wavelength is coupled to the first microresonator ring to induce Stimulated Brillouin Scattering (SBS) to provide the optical gain. ### Claim 5 (depends on 1) The integrated photonics optical gyroscope of claim 1, further comprising: a second straight waveguide to receive incoming pump light from one or more pump light sources, wherein a portion of the second straight waveguide is proximate to the first microresonator ring, and wherein the pump light provides the optical gain to counter the propagation loss. ### Claim 6 (depends on 5) The integrated photonics optical gyroscope of claim 5, wherein at least a portion of the first microresonator ring is implanted with erbium dopants that can be excited at a particular wavelength of pump light to provide the optical gain. ### Claim 7 (depends on 6) The integrated photonics optical gyroscope of claim 6, wherein the pump light is coupled to the first microresonator ring from the second straight waveguide to which the pump light is launched from one end or from both ends. ### Claim 8 (depends on 6) The integrated photonics optical gyroscope of claim 6, wherein an additional source of a pump light is disposed on top of a portion of the first microresonator ring that is implanted with the erbium dopants that can be excited at a particular wavelength of the pump light to provide the optical gain. ### Claim 9 (depends on 8) The integrated photonics optical gyroscope of claim 8, wherein a mirror is fabricated on top of the additional source of the pump light to enhance vertical injection of pump light towards the erbium dopants. ### Claim 10 (depends on 8) The integrated photonics optical gyroscope of claim 8, wherein a first pump light is coupled to the first microresonator ring from at least one side, and a second pump light is coupled to the first microresonator ring from the top. ### Claim 11 (depends on 1) The integrated photonics optical gyroscope of claim 1, wherein a heater is fabricated on top of the top vertical layer of the different physical layers to tune amount of evanescent coupling between the first portion of the first microresonator ring and the second portion of the first microresonator ring. ### Claim 12 (depends on 1) The integrated photonics optical gyroscope of claim 1, wherein at least a portion of the first microresonator ring is implanted with erbium dopants that can be excited at a particular wavelength of pump light to provide the optical gain by inducing optical resonance. ### Claim 13 (depends on 1) The integrated photonics optical gyroscope of claim 1, wherein the first microresonator ring is in a shape of a racetrack comprising: a first straight portion with a first end and a second end; a second straight portion with a first end and a second end, wherein the second straight portion is parallel to the first straight portion; a first curved portion adjoining the first end of the first straight portion to the first end of the second straight portion; and a second curved portion adjoining the second end of the first straight portion to the second end of the second straight portion. ### Claim 14 (depends on 13) The integrated photonics optical gyroscope of claim 13, wherein the optical gain is imparted the second straight portion of the first microresonator ring. ### Claim 15 (depends on 13) The integrated photonics optical gyroscope of claim 13, wherein the first straight portion of the first microresonator ring is proximate to and parallel to the first straight waveguide to facilitate evanescent coupling of light between the first straight waveguide and the first straight portion of the first microresonator ring. ### Claim 16 (depends on 13) The integrated photonics optical gyroscope of claim 13, further comprising: a second microresonator ring proximate to the second straight portion of the first microresonator ring, wherein the guided beam evanescently couples from the second straight portion of the first microresonator ring to a portion of the second microresonator ring and experiences optical gain to counter propagation loss within the first microresonator ring and the second microresonator ring. ### Claim 17 (depends on 16) The integrated photonics optical gyroscope of claim 16, wherein the optical gyroscope operates in a coupled-ring configuration, wherein the guided beam evanescently couples back from the second microresonator ring to the second straight portion of the first microresonator ring, and from the first straight portion of the first microresonator ring to the portion of the first straight waveguide to provide the optical signal for rotational sensing. ### Claim 18 (depends on 16) The integrated photonics optical gyroscope of claim 16, wherein the first microresonator ring and the second microresonator ring are fabricated on different physical layers vertically stacked on top of each other, and wherein light couples evanescently between the two physical layers that are vertically separated. ### Claim 19 (depends on 16) The integrated photonics optical gyroscope of claim 16, wherein at least a portion of the second microresonator ring is implanted with erbium dopants that can be excited at a particular wavelength of pump light to provide the optical gain.