# US 2014/0152994 A1 · Optical frequency comb stimulated brillouin scattering gyroscope > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152994 A1 - Document ID: US20140152994A1 - Status: Published application - Kind: A1 - Application number: 13/693,321 - Filed: 2012-12-04 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Assignees: Honeywell International Inc. - Applicants: Honeywell International Inc. - Inventors: Jianfeng Wu; Tiequn Qiu; Glen A. Sanders; Lee K. Strandjord - Web page: https://patentgrep.com/patent/US20140152994A1 ## CPC - H01S 3/302: {in an optical fibre} - G01C 19/727: {using a passive ring resonator} - H01S 3/30: using scattering effects, e.g. stimulated Brillouin or Raman effects - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - 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) ## Abstract Systems and methods for measuring rotation using an optical frequency comb stimulated Brillouin scattering gyroscope are provided. In certain embodiments, a system comprises a light source that produces a multiple-frequency light beam based on an optical frequency comb; and an optical fiber resonator coupled to the light source, the multiple-frequency light beam propagating in a first direction within the optical fiber resonator, wherein the multiple-frequency light beam generates stimulated Brillouin scattering (SBS) for a frequency, wherein the Brillouin scattering generates an SBS light beam to propagate in a second direction, the first direction being opposite in direction to the second direction. The system also comprises a servo to control the frequencies of the optical frequency comb to lock a plurality of component frequencies on resonance peaks of the optical fiber resonator; and a mixer that determines a frequency difference between the SBS light beam and the multiple-frequency light beam. ## Claims ### Claim 1 A system comprising: a light source configured to produce a multiple-frequency light beam based on an optical frequency comb; an optical fiber resonator coupled to the light source, the multiple-frequency light beam based on an optical frequency comb generated by the light source propagating in a first direction within the optical fiber resonator, wherein the multiple-frequency light beam based on an optical frequency comb generates stimulated Brillouin scattering for at least one frequency, wherein the Brillouin scattering generates a stimulated Brillouin scattering light beam containing at least one frequency component to propagate in the optical fiber resonator in a second direction, the first direction being opposite in direction to the second direction; at least one servo that controls the frequencies of the optical frequency comb so that a plurality of component frequencies of the optical frequency comb are locked on resonance peaks of the optical fiber resonator in the first direction; and a mixer configured to determine a frequency difference between the stimulated Brillouin scattering light beam and the multiple-frequency light beam. ### Claim 2 (depends on 1) The system of claim 1, wherein the light source generates the multiple-frequency light beam through at least one of the following methods: mode locking of a laser; supercontinuum generation or amplification; optical parametric amplification; four wave mixing; and electro-optic modulation. ### Claim 3 (depends on 1) The system of claim 1, wherein the optical fiber resonator comprises a material that has a Brillouin shift that is sufficiently large enough such that a first frequency spectrum of the multiple-frequency light beam does not overlap with a second frequency spectrum of the stimulated Brillouin scattering light beam. ### Claim 4 (depends on 1) The system of claim 1, wherein the at least one servo obtains feedback signals from processed resonator output that contains information about deviation of the plurality of component frequencies from resonance peaks in the first direction of the optical fiber resonator. ### Claim 5 (depends on 1) The system of claim 1, wherein frequency components of the optical frequency comb have a frequency separation that tracks free spectral range drift of the optical fiber resonator. ### Claim 6 (depends on 1) The system of claim 1, further comprising an optical filter configured to filter the multiple-frequency light beam such that a first frequency range of the optical frequency comb does not overlap with a second frequency range of the stimulated Brillouin scattering light beam. ### Claim 7 (depends on 6) The system of claim 6, wherein the mixer is coupled to the optical filter such that the mixer receives the multiple-frequency light beam after the multiple-frequency light beam is filtered. ### Claim 8 (depends on 1) The system of claim 1, wherein a frequency component in the plurality of frequency components at the center frequency of the optical frequency comb stimulates the Brillouin scattering in the optical fiber resonator. ### Claim 9 (depends on 1) The system of claim 1, wherein the mixer receives both the multiple-frequency light beam and the stimulated Brillouin scattering light beam from the optical fiber resonator. ### Claim 10 (depends on 1) The system of claim 1, further comprising at least one attenuator configured to attenuate at least one of the multiple-frequency light beam and the stimulated Brillouin scattering light beam before the mixer determines the frequency difference between the stimulated Brillouin scattering light beam and the multiple-frequency light beam. ### Claim 11 A gyroscope comprising: an optical fiber resonator; a light source configured to provide a multiple-frequency light beam based on an optical frequency comb to the optical fiber resonator, the multiple-frequency light beam propagating through the optical fiber resonator in a first direction within the optical fiber resonator, wherein the multiple-frequency light beam stimulates Brillouin scattering for at least one frequency, the Brillouin scattering causing a stimulated Brillouin scattering light beam containing at least one frequency component to propagate in the optical fiber resonator in a second direction, the first direction being opposite in direction to the second direction, wherein a plurality of frequency components in the multiple-frequency light beam are locked to resonance peaks of the optical fiber resonator and the plurality of frequency components have a frequency separation that tracks free spectral range drift of the optical fiber resonator; a mixer configured to determine a frequency difference between the at least one stimulated Brillouin scattering light beam and the multiple-frequency light beam; and a rate output coupled to the mixer, the rate output configured to determine the rate of rotation based on the frequency difference. ### Claim 12 (depends on 11) The gyroscope of claim 11, further comprising a free spectral range control coupled between the optical fiber resonator and the light source, the free spectral range control configured to adjust the frequency separation of the multiple-frequency light beam to track the free spectral range of the optical fiber resonator. ### Claim 13 (depends on 11) The gyroscope of claim 11, wherein the optical fiber resonator comprises a material that has a Brillouin shift that is sufficiently large enough such that a first frequency range of the multiple-frequency light beam does not overlap with a second frequency range of the stimulated Brillouin scattering light beam. ### Claim 14 (depends on 11) The gyroscope of claim 11, further comprising an optical filter configured to filter the spectrum of the multiple-frequency light beam such that a first frequency range of the multiple-frequency light beam does not overlap with a second frequency range of the stimulated Brillouin scattering light beam. ### Claim 15 (depends on 14) The gyroscope of claim 14, wherein the mixer is coupled to the optical filter such the mixer receives the multiple-frequency light beam after the multiple-frequency light beam is filtered. ### Claim 16 (depends on 11) The gyroscope of claim 11, wherein a center frequency of the multiple-frequency light beam stimulates Brillouin scattering in the optical fiber resonator. ### Claim 17 (depends on 11) The gyroscope of claim 11, wherein the mixer receives both the multiple-frequency light beam and the stimulated Brillouin scattering light beam from the optical fiber resonator. ### Claim 18 A method for measuring rotation, the method comprising: propagating a multiple-frequency light beam based on an optical frequency comb through an optical fiber resonator in a first direction, wherein the multiple-frequency light beam stimulates a stimulated Brillouin scattering light beam containing at least one frequency component, the stimulated Brillouin scattering light beam propagating through the optical fiber resonator in a second direction, wherein the first direction is opposite to the second direction; mixing the multiple-frequency light beam with the stimulated Brillouin scattering light beam to produce at least one signal representing the frequency difference between the multiple-frequency light beam and the stimulated Brillouin scattering light beam; and determining the rate of rotation based on the frequency difference. ### Claim 19 (depends on 18) The method of claim 18, further comprising controlling a light source that produces the multiple-frequency light beam such that a plurality of frequency components of the multiple-frequency light beam are locked to resonance peaks of the optical fiber resonator and have a frequency separation that tracks free spectral range drift of the optical fiber resonator. ### Claim 20 (depends on 18) The method of claim 18, further comprising filtering the multiple-frequency light beam such that a first frequency range of the multiple-frequency light beam does not overlap with a second frequency range of the stimulated Brillouin scattering light beam.