Unidirectional crow gyroscope

• US 8,068,232 B2
• Filed: 04/01/2009
• Issued: 11/29/2011
• Est. Priority Date: 04/01/2008
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Fan, Shanhui, Terrel, Matthew A., Digonnet, Michel J. F.
• Primary Examiner(s): Chowdhury; Tarifur
• Assistant Examiner(s): Cook; Jonathon
• Application Number:
  US12/416,767
• Publication Number:
  US 20090244544A1
• Time in Patent Office: 972 Days
• Field of Search: 356459-461
• US Class Current: 356/461
• CPC Class Codes: G01C 19/721 Details
• CPC Class Codes: G01C 19/727 using a passive ring resonator

Abstract

An optical waveguide gyroscope includes at least one optical coupler configured to receive a first optical signal at a first port, to transmit a second optical signal to a second port, and to transmit a third optical signal to a third port. The optical waveguide gyroscope further includes a plurality of resonant waveguides optically coupled to the second port and the third port. The resonant waveguides are generally adjacent to one another and optically coupled to one another. At least a portion of the second optical signal propagates from the second port to the third port by propagating through the plurality of resonant waveguides, and at least a portion of the third optical signal propagates from the third port to the second port by propagating through the plurality of resonant waveguides. The at least a portion of the second optical signal propagates through each resonant waveguide of the plurality of resonant waveguides in a clockwise direction and the at least a portion of the third optical signal propagates through each resonant waveguide of the plurality of resonant waveguides in a counterclockwise direction.

Claims

1. An optical waveguide gyroscope comprising a plurality of resonant waveguides adjacent to one another and optically coupled together, wherein each resonant waveguide of the plurality of resonant waveguides is configured to allow light to propagate along the resonant waveguide in a planar path, wherein the plurality of resonant waveguides comprises at least two resonant waveguides comprising a first resonant waveguide configured to allow light to propagate along the first resonant waveguide in a first path and a second resonant waveguide adjacent to the first resonant waveguide and configured to allow light to propagate along the second resonant waveguide in a second path, wherein the first resonant waveguide and the second resonant waveguide are optically coupled in a way that at least a portion of light propagates either successively through the first resonant waveguide along the first path in a clockwise direction and through the second resonant waveguide along the second path in a clockwise direction or successively through the first resonant waveguide along the first path in a counterclockwise direction and through the second resonant waveguide along the second path in a counterclockwise direction.

2. The optical waveguide gyroscope of claim 1, wherein at least one of the resonant waveguides comprises at least one ring waveguide.

3. The optical waveguide gyroscope of claim 1, wherein at least one of the resonant waveguides comprises at least one microresonator.

4. The optical waveguide gyroscope of claim 1, wherein the resonant waveguides are positioned such that the planar paths of the plurality of resonant waveguides are in a common plane.

5. The optical waveguide gyroscope of claim 4, wherein the resonant waveguides are positioned along a straight line.

6. The optical waveguide gyroscope of claim 4, wherein the resonant waveguides are positioned along a curved line.

7. The optical waveguide gyroscope of claim 1, wherein each planar path has a normal direction perpendicular to the path, and the resonant waveguides are positioned such that the normal directions of the paths are coincident with one another.

8. The optical waveguide gyroscope of claim 1, wherein at least one of the resonant waveguides includes a twisted portion optically coupled to an adjacent resonant waveguide.

9. The optical waveguide gyroscope of claim 1, wherein at least one of the resonant waveguides is optically coupled to an adjacent resonant waveguide by a ring waveguide having an area smaller than an area of the at least one of the resonant waveguides.

10. The optical waveguide gyroscope of claim 1, wherein a coupling ratio between adjacent resonant waveguides of the plurality of resonant waveguides is less than one.

11. An optical waveguide gyroscope comprising:

at least one optical coupler having a first port, a second port, and a third port, the at least one optical coupler configured to receive a first optical signal at the first port, to transmit a second optical signal to the second port, and to transmit a third optical signal to the third port; and

a plurality of resonant waveguides optically coupled to the second port and the third port, the resonant waveguides adjacent to one another and optically coupled to one another, wherein at least a portion of the second optical signal propagates from the second port to the third port by propagating through the plurality of resonant waveguides, and at least a portion of the third optical signal propagates from the third port to the second port by propagating through the plurality of resonant waveguides, wherein the plurality of resonant waveguides comprises at least two resonant waveguides comprising a first resonant waveguide configured to allow at least a portion of the second optical signal to propagate along the first resonant waveguide in a first path and a second resonant waveguide adjacent to the first resonant waveguide and configured to allow the at least a portion of the second optical signal to propagate along the second resonant waveguide in a second path, wherein the first resonant waveguide and the second resonant waveguide are optically coupled in a way that the at least a portion of the second optical signal propagates either successively through the first resonant waveguide along the first path in a clockwise direction and through the second resonant waveguide along the second path in a clockwise direction or successively through the first resonant waveguide along the first path in a counterclockwise direction and through the second resonant waveguide along the second path in a counterclockwise direction.

12. The optical waveguide gyroscope of claim 11, wherein the first resonant waveguide is configured to allow at least a portion of the third optical signal to propagate along the first resonant waveguide in a third path and the second resonant waveguide is configured to allow the at least a portion of the third optical signal to propagate along the second resonant waveguide in a fourth path, wherein the first resonant waveguide and the second resonant waveguide are optically coupled in a way that the at least a portion of the third optical signal propagates either successively through the second resonant waveguide along the fourth path in a clockwise direction and through the first resonant waveguide along the third path in a clockwise direction or successively through the second resonant waveguide along the fourth path in a counterclockwise direction and through the first resonant waveguide along the third path in a counterclockwise direction.

13. The optical waveguide gyroscope of claim 11, further comprising a plurality of optical couplers, each optical coupler between and optically coupling two adjacent resonant waveguides of the plurality of resonant waveguides to one another.

14. The optical waveguide gyroscope of claim 13, wherein at least one optical coupler of the plurality of optical couplers comprises a ring resonator optically coupled to a first resonant waveguide of the plurality of resonant waveguides and to a second resonant waveguide of the plurality of resonant waveguides.

15. The optical waveguide gyroscope of claim 14, wherein the first resonant waveguide is planar and surrounds a first area, the second resonant waveguide is planar and surrounds a second area, and the ring resonator is planar and surrounds a third area, the third area smaller than the first area and smaller than the second area.

16. The optical waveguide gyroscope of claim 15, wherein the third area is less than 10% of the first area and less than 10% of the second area.

17. The optical waveguide gyroscope of claim 11, further comprising a plurality of optically coupling portions, each optically coupling portion optically coupling two adjacent resonant waveguides of the plurality of resonant waveguides to one another, wherein at least one optical coupling portion of the plurality of optically coupling portions comprises a first portion of a first resonant waveguide of the plurality of resonant waveguides, the first portion adjacent to a second resonant waveguide of the plurality of waveguides and optically coupled to the second resonant waveguide, wherein the first portion comprising two sections of the first resonant waveguide that cross over one another.

18. The optical waveguide gyroscope of claim 17, wherein the coupling portion comprises a 180 degree twist of the first resonant waveguide, the first resonant waveguide is planar and surrounds a first area, the coupling portion is planar and surrounds a second area less than 10% of the first area.

19. The optical waveguide gyroscope of claim 11, wherein the at least a portion of the second optical signal and the at least a portion of the third optical signal are combined by the optical coupler and transmitted to the first port.

20. The optical waveguide gyroscope of claim 11, wherein each of the at least two resonant waveguides is planar, and the at least two resonant waveguides are parallel to one another.

21. The optical waveguide gyroscope of claim 20, wherein the at least two resonant waveguides are planar with one another.

22. The optical waveguide gyroscope of claim 21, wherein the at least two resonant waveguides are positioned along a straight line.

23. The optical waveguide gyroscope of claim 21, wherein the at least two resonant waveguides are positioned along a curved line.

24. The optical waveguide gyroscope of claim 20, wherein each of the at least two resonant waveguides defines a normal direction perpendicular to the resonant waveguide, and the at least two resonant waveguides are positioned such that the normal directions are coincident with one another.

25. The optical waveguide gyroscope of claim 20, wherein the at least two resonant waveguides are stacked above one another.

26. An optical waveguide gyroscope comprising a plurality of resonant waveguides adjacent to one another and optically coupled together, wherein each resonant waveguide of the plurality of resonant waveguides is configured to allow light to propagate through the resonant waveguide in a planar path, wherein the paths of each of the resonant waveguides of the plurality of resonant waveguides are parallel to one another, wherein at least one of the resonant waveguides includes a twisted portion optically coupled to an adjacent resonant waveguide, wherein light propagates along each path in a clockwise direction or along each path in a counterclockwise direction.