Ring laser gyroscope that does not require mirrors

• US 7,245,381 B2
• Filed: 12/20/2004
• Issued: 07/17/2007
• Est. Priority Date: 12/20/2004
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Tazartes, Daniel A., Marino, Kenneth, Volk, Charles
• Primary Examiner(s): Turner; Samuel A.
• Application Number:
  US11/017,446
• Publication Number:
  US 20060132788A1
• Time in Patent Office: 939 Days
• Field of Search: 356459-461, 372/94
• US Class Current: 356/461
• CPC Class Codes: G01C 19/64 Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
• CPC Class Codes: G01C 19/72 with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers

Abstract

In an embodiment of a ring laser gyroscope, a hollow bandgap fiber is filled with a gas or material that will generate laser beams within the fiber upon being excited by an energy source. A detector coupled to the fiber detects a standing wave pattern within the fiber, wherein changes in the detected standing wave pattern indicates a corresponding change in the orientation of the fiber.

Claims

1. A laser gyroscope comprising:

a hollow photonic fiber with first and second ends connected together to form a hollow chamber of a continuous loop;

a source of energy;

a material disposed within the hollow chamber that will lase upon receiving energy from the source of energy thereby producing a laser beam within the continuous loop of the hollow chamber; and

a detector coupled to the fiber and adapted to measure changes in a standing wave pattern in the laser beam relative to a detector.

2. The laser gyroscope of claim 1 wherein first and second laser beams propagate in opposite directions within the hollow fiber.

3. The laser gyroscope of claim 2 wherein the detector extracts a portion of the first and second beams and causes the first and second beams to interfere.

4. The laser gyroscope of claim 2 wherein the detector measures changes in a standing wave pattern of the first and second laser beams relative to the detector.

5. The laser gyroscope of claim 1 wherein the fiber is a photonic bandgap fiber.

6. The laser gyroscope of claim 1 wherein the material disposed within the hollow chamber is a gas.

7. The laser gyroscope of claim 5 wherein the gas is a mixture of helium and neon gas.

8. The laser gyroscope of claim 2 wherein the detector comprises an optical detector adapted to measure the intensity of light of a wavelength utilized by the laser beam.

9. The laser gyroscope of claim 1 wherein the source of energy comprises a source of radio frequency energy.

10. The laser gyroscope of claim 9 further comprising a coil that surrounds at least a portion of the fiber and is coupled to the source of radio frequency energy, the coil serving to couple radio frequency energy to the material disposed within the hollow chamber.

11. The laser gyroscope of claim 2 further comprising a signal processor coupled to an output of the detector, the signal processor adapted to provide a digital output signal that corresponds to the output from the detector, wherein the digital output signal indicates a current orientation of the fiber.

12. The laser gyroscope of claim 11 wherein the current orientation of the fiber indicates a rotational orientation of the fiber in the plane of the fiber.

13. The laser gyroscope of claim 1 further comprising a substantially planar base that supports the fiber.

14. The laser gyroscope of claim 13 wherein the fiber is disposed within a plane, and the plane of the fiber is substantially parallel to the planar base.

15. The laser gyroscope of claim 1 wherein a longitudinal centerline of the fiber is disposed within a plane.

16. A method for determining a second orientation of a movable object relative to a first orientation comprising the steps of:

forming a continuous loop of a hollow photonic fiber to form a hollow chamber within the continuous loop;

disposing a material that will lase within the hollow chamber;

mounting the continuous loop of hollow photonic fiber to the movable object;

supplying energy to the material causing a laser beam to be produced within the hollow chamber;

detecting changes in a standing wave pattern in the laser beam relative to the first orientation of the fiber whereby the changes in the standing wave pattern corresponds to a changed orientation of the movable object from the first to the second orientation;

conveying orientation information to a user about the movable object based on the detected changes.

17. The method according to claim 16 wherein the step of disposing a material that will lase within the hollow chamber consists of disposing a gas that will lase within the hollow chamber.

18. The method according to claim 16 wherein the step of mounting the continuous loop of hollow photonic fiber to the movable object comprises mounting the continuous loop of hollow photonic fiber within a first plane associated with the movable object and wherein the changes in the standing wave pattern corresponds to a changed orientation of the movable object to the second orientation in the first plane relative to the first orientation in the first plane.

19. A ring laser gyroscope comprising:

a hollow photonic bandgap fiber formed into a continuous loop defining a hollow, continuous loop, chamber;

a material disposed within the hollow chamber adapted to generate counterpropagating first and second laser beams upon receiving energy from an energy source;

a detector adapted to measure changes in a standing wave pattern of the laser beams relative to a location on the fiber, wherein changes in the standing wave pattern correspond to changes in orientation of the fiber.

20. The laser gyroscope of claim 19 wherein the detector is coupled to the fiber and adapted to extract a portion of the counterpropagating first and second beams and cause them to interfere.

21. The ring laser gyroscope of claim 19 wherein a longitudinal centerline of the fiber is disposed substantially in a first plane, the detector adapted to measure changes in the standing wave pattern of the laser beam wherein the changes correspond to changes in orientation of the fiber in the first plane.

22. The ring laser gyroscope of claim 19 wherein the material comprises a gas that will lase.

23. The ring laser gyroscope of claim 19 wherein the energy source comprises a source of radio frequency energy coupled to the material by a coil that encircles the fiber.

24. The ring laser gyroscope of claim 19 further comprising a signal processor coupled to an output of the detector wherein the signal processor is adapted to provide a digital output signal corresponding to the orientation of the fiber.

25. A laser gyroscope comprising:

a photonic bandgap fiber with first and second ends connected together to form a continuous loop;

a source of energy;

a material disposed within the fiber that will lase upon receiving energy from the source of energy adapted to produce first and second counterpropagating laser beams within the continuous loop of the hollow chamber; and

a detector coupled to the fiber and adapted to extract a portion of the counterpropagating first and second beams and cause them to interfere.

26. The laser gyroscope of claim 25 wherein the first and second laser beams propagate in opposite directions within the fiber.

27. The laser gyroscope of claim 25 wherein the detector measures changes in a standing wave pattern in the first and second laser beams relative to the detector.

28. The laser gyroscope of claim 25 wherein the material disposed within the hollow chamber is a gas.

29. The laser gyroscope of claim 25 wherein the material disposed within the hollow chamber is a solid.

30. The laser gyroscope of claim 25 wherein the material disposed within the hollow chamber is a liquid.

31. The laser gyroscope of claim 25 wherein the detector comprises an optical detector adapted to measure the intensity of light of a wavelength utilized by the first and second laser beams.

32. The laser gyroscope of claim 25 wherein the source of energy comprises a source of radio frequency energy.

33. The laser gyroscope of claim 32 further comprising a coil that surrounds at least a portion of the fiber and is coupled to the source of radio frequency energy, the coil serving to couple radio frequency energy to the material disposed within the hollow chamber.

34. The laser gyroscope of claim 25 further comprising a signal processor coupled to an output of the detector, the signal processor adapted to provide a digital output signal that corresponds to the output from the detector, wherein the digital output signal indicates a current orientation of the fiber.

35. The laser gyroscope of claim 34 wherein the current orientation of the fiber indicates a rotational orientation of the fiber in the plane of the fiber.

36. The laser gyroscope of claim 25 further comprising a substantially planar base that supports the fiber.

37. The laser gyroscope of claim 36 wherein the fiber is disposed within a plane, and the plane of the fiber is substantially parallel to the planar base.

38. The laser gyroscope of claim 36 wherein a longitudinal centerline of the fiber is disposed within a plane.