Resonator optical gyroscopes with dual broadband light sources

Patent metadata

Field	Value
Publication number	US-12405111-B2
Application number	US-202318348169-A
Country	US
Kind code	B2
Filing date	Jul 6, 2023
Priority date	Jul 6, 2023
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

A gyroscope comprises first and second light sources that emit first and second beams with broadband spectrums, and a waveguide arrangement that communicates with the light sources. A resonator communicates with the waveguide arrangement to receive the beams. A first circulator is coupled to the waveguide arrangement between the first light source and the resonator. A second circulator is coupled to the waveguide arrangement between the second light source and the resonator. A first rate detector communicates with the resonator through the first circulator, and a second rate detector communicates with the resonator through the second circulator. The rate detectors produce rate measurements based on a detected resonance frequency shift of the beams in the resonator caused by rotation of the gyroscope. Outputs of the rate detectors are used to calculate a rotation rate that is corrected for errors due to a time varying pathlength change in the resonator.

First claim

What is claimed is:

1. A gyroscope comprising:
a first light source configured to emit a first light beam with a broadband spectrum, and a second light source configured to emit a second light beam with a broadband spectrum;
a first waveguide arrangement in optical communication with the first and second light sources;
an optical resonator having a first side and an opposing second side, the optical resonator in optical communication with the first waveguide arrangement on the first side, the optical resonator configured to receive the first and second light beams through the first waveguide arrangement;
a second waveguide arrangement in optical communication with the optical resonator on the second side thereof;
a first phase modulator in optical communication with the optical resonator through the second waveguide arrangement, and a first reflector optically coupled with the first phase modulator;
a second phase modulator in optical communication with the optical resonator through the second waveguide arrangement, and a second reflector optically coupled with the second phase modulator;
a first optical circulator optically coupled to the first waveguide arrangement between the first light source and the first side of the optical resonator, and a second optical circulator optically coupled to first waveguide arrangement between the second light source and the first side of the optical resonator; and
a first rate detector in optical communication with the optical resonator through the first optical circulator, and a second rate detector in optical communication with the optical resonator through the second optical circulator;
wherein the first and second rate detectors are operative to produce respective first and second rate measurements based on a detected resonance frequency shift of the beams in the optical resonator caused by rotation of the gyroscope;
wherein outputs of the first and second rate detectors are used to calculate a rotation rate that is corrected for errors due to a time varying pathlength change in the optical resonator.

2. The gyroscope of claim 1 , wherein a portion of the first light beam is optically coupled into the optical resonator from the first waveguide arrangement and propagates in a counterclockwise (CCW) direction as a first CCW beam, and a portion of the second light beam is optically coupled into the optical resonator from the first waveguide arrangement and propagates in a clockwise (CW) direction as a first CW beam.

3. The gyroscope of claim 2 , wherein:
the first CCW beam is coupled out of the optical resonator into the second waveguide arrangement and directed to the first phase modulator and the first reflector, which respectively modulate and reflect the CCW beam as a first reflected beam back along the second waveguide arrangement, which optically couples the first reflected beam into the optical resonator to propagate in the CW direction as a second CW beam in the optical resonator; and
the CW beam is coupled out of the optical resonator into the second waveguide arrangement and directed to the second phase modulator and the second reflector, which respectively modulate and reflect the CW beam as a second reflected beam back along the second waveguide arrangement, which optically couples the second reflected beam into the optical resonator to propagate in the CCW direction as a second CCW beam in the optical resonator.

4. The gyroscope of claim 3 , wherein:
the second CW beam is coupled out of the optical resonator and directed to the first rate detector by the first optical circulator; and
the second CCW beam is coupled out of the optical resonator and directed to the second rate detector by the second optical circulator.

5. The gyroscope of claim 4 , further comprising:
a first intensity detector in optical communication with the second waveguide arrangement through a first polarizing coupler; and
a second intensity detector in optical communication with the second waveguide arrangement through a second polarizing coupler.

6. The gyroscope of claim 5 , wherein:
a portion of the first reflected beam is directed to the first intensity detector by the first polarizing coupler, wherein the first intensity detector monitors a power of the first reflected beam; and
a portion of the second reflected beam is directed to the second intensity detector by the second polarizing coupler, wherein the second intensity detector monitors a power of the second reflected beam.

7. The gyroscope of claim 6 , further comprising:
a first low frequency phase modulator optically coupled to the second waveguide arrangement between the first phase modulator and the first polarizing coupler; and
a second low frequency phase modulator optically coupled to the second waveguide arrangement between the second phase modulator and the second polarizing coupler.

8. The gyroscope of claim 4 , wherein:
the first CCW beam is modulated at a first frequency by the first phase modulator; and
the first CW beam is modulated at a second frequency by the second phase modulator, wherein the second frequency is different than the first frequency.

9. The gyroscope of claim 4 , wherein the first and second light sources are configured to separately switch on and off at different times, such that the first and second rate measurements from the first and second rate detectors are separated by time.

10. The gyroscope of claim 4 , further comprising:
a first optical filter optically coupled to the first waveguide arrangement between the first optical circulator and the first side of the optical resonator; and
a second optical filter optically coupled to the first waveguide arrangement between the second optical circulator and the first side of the optical resonator;
wherein the second optical filter is configured to filter out a beam having a first wavelength, and the first optical filter is configured to filter out a beam having a second wavelength that is different than the first wavelength.

11. The gyroscope of claim 10 , wherein the first light source is configured to emit the first light beam at the first wavelength, and the second light source is configured to emit the second light beam at the second wavelength.

12. The gyroscope of claim 1 , wherein the first and second light sources comprise amplified spontaneous emission devices, or superluminescent diodes.

13. The gyroscope of claim 1 , wherein the optical resonator comprises a waveguide ring resonator.

14. The gyroscope of claim 1 , wherein the optical resonator comprises a fiber ring resonator.

15. The gyroscope of claim 1 , wherein the optical resonator comprises a planar waveguide ring resonator.

16. The gyroscope of claim 5 , wherein the first waveguide arrangement comprises:
a first input waveguide optically coupled between the first light source and a first port of the first optical circulator;
a second input waveguide optically coupled between the second light source and a first port of the second optical circulator;
a first bus waveguide optically coupled between a second port of first optical circulator and a second port of second optical circulator, wherein the first bus waveguide is optically coupled to the optical resonator at a first coupler region;
a first output waveguide optically coupled between a third port of the first optical circulator and the first rate detector; and
a second output waveguide optically coupled between a third port of the second optical circulator and the second rate detector.

17. The gyroscope of claim 16 , wherein the second waveguide arrangeme

Assignees

• Honeywell Int Inc

Inventors

• Wu Jianfeng
• Qiu Tiequn
• Sanders Glen A
• Tin Steven
• Puckett Matthew Wade

Classifications

• G01C19/72

  with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers · CPC title

• G01C19/64

  Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams · CPC title

• G01C19/722

  of the mechanical construction · CPC title

• G01C19/727 Primary

  using a passive ring resonator · CPC title

• G01C19/661 Primary

  details · CPC title