FIBER SHAPE SENSING SYSTEMS AND METHODS

• US 20110090486A1
• Filed: 07/15/2010
• Published: 04/21/2011
• Est. Priority Date: 07/15/2009
• Status: Active Grant

• Current Assignee: Auris Health, Inc. (Johnson & Johnson)
• Original Assignee: Hansen Medical Incorporated (Johnson & Johnson)
• Inventors: UDD, Eric
• Granted Patent: US 8,780,339 B2
• Time in Patent Office: Days
• US Class Current: 356/73.1
• CPC Class Codes: A61B 1/009 with bending or curvature detection of the insertion part
• CPC Class Codes: A61B 2034/2061 using shape-sensors, e.g. fiber shape sensors with Bragg gratings
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 50/10 Furniture specially adapted for surgical or diagnostic appliances or instruments
• CPC Class Codes: A61B 50/15 Mayo stands; Tables
• CPC Class Codes: G01B 11/18 using photoelastic elements
• CPC Class Codes: G01D 5/35316 using a Bragg gratings
• CPC Class Codes: G01D 5/35383 using multiple sensor devices using multiplexing techniques
• CPC Class Codes: G01D 5/35387 using wavelength division multiplexing

Abstract

In certain variations, fiber shape sensing or measuring systems, devices and methods are described herein, which allow for measurement of three dimensional bending as well as twist measurements of various fibers, e.g., optical fibers and fiber optic probes of various sizes. In certain variations, the systems are designed to take advantage of unique light guiding properties of optical fibers and various fiber gratings.

Claims

1. A shape measuring system comprising:

three or more optical fibers, wherein the fibers have a bonded region to support strain transfer between the optical fibers; and

wherein each of the optical fibers has a fiber grating on each of the optical fibers along the bonded region.

2. A shape measuring system according to claim 1, wherein the bonded region of the fibers is tapered and fusion bonded and configured such that a bend of an optical fiber may be determined by measuring a spectral profile of a reflection from the fiber grating bonded region.

3. A shape measuring system according to claim 1, wherein the fibers are drawn and heated to establish a tapered bonded region wherein the surfaces of the fibers are bonded for strain transfer between the fibers.

4. A shape measuring system according to claim 1, wherein each of the optical fibers has a fiber grating written into the same position on each of the optical fibers along the bonded region.

5. A shape measuring system according to claim 1, wherein a plurality of fiber gratings of different wavelengths are written into the bonded region.

6. A shape measuring system according to claim 1, wherein a chirped fiber grating is written into the bonded fiber region.

7. A shape measuring system according to claim 1, wherein low reflectivity fiber gratings of substantially the same wavelength are written into the bonded region.

8. A shape measuring system according to claim 1, wherein the bonded region has a cleaved end.

9. A shape measuring system according to claim 8, wherein the cleaved end comprises an antireflection coating.

10. A shape measuring system according to claim 8, wherein the cleaved end is melted to form a nonreflecting end.

11. A shape measuring system according to claim 8, wherein the cleaved end is angled.

12. A shape measuring system according to claim 1, wherein the fiber grating is an angled or tilted fiber grating to support twist measurements.

13. A shape measuring system according to claim 1, wherein the fiber grating is a birefringent fiber grating to support twist measurements.

14. A shape measuring system according to claim 1, wherein the optical fibers are polarization preserving optical fibers.

15. A shape measuring system according to claim 14, wherein the polarization preserving optical fibers are elliptical core optical fibers.

16. A shape measuring system according to claim 14, wherein the polarization preserving optical fibers have at least one flattened side.

17. A shape measuring system according to claim 1, further comprising an end region wherein the optical fibers are mechanically independent such that the fibers can be interfaced to connectors or spliced.

18. A shape measuring system according to claim 1, wherein the bonded region is configured such that when light is coupled into any one of the optical fibers there is minimal or no cross coupling in the bonded region between any of the optical fibers.

19. A shape measuring system according to claim 1, wherein the optical fibers extend along an axis of an elongate member of a surgical system for sensing the bend and/or twist of the elongate member.

20. A shape measuring system according to claim 19, wherein the elongate member is manually or robotically controlled.

25. A shape measuring system according to claim 20, wherein the fiber grating is an angled or tilted fiber grating to support twist measurements.

21. A shape measuring system comprising:

a large core optical fiber wherein a fiber grating is written onto said optical fiber; and

a spectral read out system configured to measure a property of a reflection of light from the fiber grating.

22. A shape measuring system according to claim 21, wherein the large core optical fiber has a diameter of greater than 20 microns.

23. A shape measuring system according to claim 21, further comprising a light source for illuminating the fiber grating.

24. A shape measuring system according to claim 21, wherein a bend of the optical fiber may be determined by measuring a spectral profile of the reflection.

26. A shape measuring system according to claim 21, wherein an effective period or spacing of the fiber grating varies across the core of the optical fiber.

27. A shape measuring system according to claim 21, wherein the optical fiber has an index of refraction gradient across its core.

28. A shape measuring system according to claim 27, wherein the index of refraction gradient is linear.

29. A shape measuring system according to claim 28, wherein the optical fiber has birefringent axes.

30. A shape measuring system according to claim 29, wherein the optical fiber has index of refraction gradients along each birefringent axis.

31. A shape measuring system according to claim 30, wherein the optical fiber has at least one tilted fiber grating.

32. A shape measuring system according to claim 31, wherein the tilted fiber grating is written along an axis that is not on one of the birefringent axes.

33. A shape measuring system according to claim 21, wherein the fiber grating is a birefringent fiber grating to support twist measurements.

34. A shape measuring system according to claim 21, wherein the optical fiber extends along an axis of an elongate member of a surgical system for sensing the bend and/or twist of the elongate member.

35. A shape measuring system according to claim 34, wherein the elongate member is manually or robotically controlled.

36. A system for measuring twist comprising:

a light beam director;

an optical fiber having a first reference tilted fiber grating, a second tilted fiber grating and an end reflector;

a polarizer; and

a spectrometer, wherein the light beam director is configured to receive a light beam such that at least a portion of the light beam is directed from the light beam director into the optical fiber, the end reflector being configured to reflect the at least a portion of the light beam back through the tilted fiber gratings to the light beam director, through a polarizer and onto a spectrometer to measure twist along the optical fiber at points associated with a tilted fiber grating.

37. The system of claim 36, wherein a polarization state of a wavelength associated with a fiber grating is detected such that twist along a region of the fiber associated with the fiber grating can be measured.

38. The system of claim 36, wherein the light beam director is a directional coupler having a first port, second port and an output port, and the system further comprises a light source adapted to couple the light beam into the first port of the directional coupler, wherein at least a portion of the light beam is directed by the second port of the directional coupler into the optical fiber, the end reflector being configured to reflect the light beam back through the tilted fiber gratings to the directional coupler where the light beam is directed by the output port of the directional coupler through a polarizer and onto a spectrometer.

39. The system of claim 36, wherein the light beam director is a directional coupler.

40. The system of claim 36, wherein the optical fiber has an array of second tilted fiber gratings.

41. The system of claim 36, wherein the end reflector is a metallic coating.

42. The system of claim 36, wherein the end reflector is a dielectric coating of one or more layers.

43. The system of claim 36, wherein the end reflector is a directional coupler with a fiber loop connecting two coupler ports of the end reflector directional coupler.

44. The system of claim 36, wherein an output port of the light beam director is configured to direct the light beam to a polarizing beamsplitter, the polarizing beamsplitter having two outputs which are directed to a 2×

1 switch, the 2×

1 switch having an output directed to an output spectrometer.

45. The system of claim 36, wherein an output port of the light beam director is configured to direct the light beam to a polarizing beamsplitter, the polarizing beamsplitter having two outputs which are directed to a first output spectrometer and a second output spectrometer.

46. The system of claim 36, wherein the optical fiber extends along an axis of an elongate member of a surgical system for sensing the twist of the elongate member.

47. The system of claim 46, wherein the elongate member is manually or robotically controlled.

48. A method for measuring twist along a fiber comprising:

coupling a light beam into a light beam director;

directing at least a portion of the light beam from the light beam director into an optical fiber, the optical fiber having a first reference tilted fiber grating, a second tilted fiber grating and an end reflector;

reflecting the light beam back through the tilted fiber gratings to the light beam director, through a polarizer and onto a spectrometer; and

detecting a polarization state of a wavelength associated with a fiber grating to measure twist along a region of the fiber associated with the fiber grating.

49. The method of claim 48, wherein the light beam director is a directional coupler having a first port, second port and an output port, and the system further comprises a light source adapted to couple the light beam into the first port of the directional coupler, wherein at least a portion of the light beam is directed by the second port of the directional coupler into the optical fiber, the end reflector being configured to reflect the light beam back through the tilted fiber gratings to the directional coupler where the light beam is directed by the output port of the directional coupler through a polarizer and onto a spectrometer.

50. The method of claim 48, wherein the light beam director is a directional coupler.

51. The method of claim 48, wherein the optical fiber has an array of second tilted fiber gratings.

52. The method of claim 48, wherein the end reflector is a metallic coating.

53. The method of claim 48, wherein the end reflector is a dielectric coating of one or more layers.

54. The method of claim 48, wherein the end reflector is a directional coupler with a fiber loop connecting two coupler ports of the end reflector directional coupler.

55. The method of claim 48, wherein an output port of the light beam director directs the light beam to a polarizing beamsplitter, the polarizing beamsplitter having two outputs which are directed to a 2×

1 switch, the 2×

1 switch having an output directed to an output spectrometer.

56. The method of claim 48, wherein an output port of the light beam director directs the light beam to a polarizing beamsplitter, the polarizing beamsplitter having two outputs which are directed to a first output spectrometer and a second output spectrometer.

57. The method of claim 48, further comprising sensing twist of an elongate member of a surgical system wherein the optical fiber extends along an axis of the elongate member.

58. The system of claim 57, wherein the elongate member is manually or robotically controlled.

59. A system for measuring twist comprising:

a light beam director;

an optical fiber having a birefringent fiber grating;

a polarizer; and

a spectrometer, wherein the light beam director is configured to receive a light beam such that at least a portion of the light beam is directed from the light beam director to the birefringent fiber grating of the optical fiber, the birefringent fiber grating being configured to at least partially reflect the light beam back to the light beam director, which directs the light beam through a polarizer and onto a spectrometer to measure twist along the optical fiber.

60. The system of claim 59, wherein the birefringent fiber grating is polarization dependent and the polarization state of the reflected light beam is detected to measure twist.

61. The system of claim 59, wherein a reflection spectra of the fiber grating is split into two distinct spectral peaks that are polarization dependent where the relative amplitudes of the spectral peaks and change in their ratio can be used to measure twist.

62. The system of claim 59, wherein the light beam director is a circulator.

63. The system of claim 59, wherein the light beam director is a circulator having a first port, second port and an output port, and the system further comprises a light source adapted to couple the light beam into the first port of the circulator, wherein at least a portion of the light beam is directed by the second port of the circulator into the birefringent fiber grating of the optical fiber, the birefringent fiber grating at least partially reflects the light beam back to the circulator where the light beam is directed by the output port of the circulator through a polarizer and onto a spectrometer.

64. The system of claim 59, wherein light beam director is a fused biconical taper.

65. The system of claim 59, wherein the optical fiber is low birefringence optical fiber and the birefringent grating is written onto the optical fiber.

66. The system of claim 59, wherein the optical fiber extends along an axis of an elongate member of a surgical system for sensing the twist of the elongate member.

67. The system of claim 66, wherein the elongate member is manually or robotically controlled.

68. A method for measuring twist along a fiber comprising:

coupling a light beam into a light beam director;

directing at least a portion of the light beam from the light beam director into an optical fiber, the optical fiber having a birefringent fiber grating;

reflecting at least a portion of the light beam off of the birefringent fiber grating toward the light beam director, through a polarizer and onto a spectrometer;

splitting a reflection spectra of the fiber grating into two distinct spectral peaks that are polarization dependent; and

detecting the relative amplitudes of the spectral peaks and change in their ratio to measure twist along the fiber.

69. The method of claim 68, wherein the birefringent fiber grating is polarization dependent and the polarization state of the reflected light beam is detected to measure twist.

70. The method of claim 68, wherein the light beam director is a circulator.

71. The method of claim 68, wherein the light beam director is a circulator having a first port, second port and an output port, and the system further comprises a light source adapted to couple the light beam into the first port of the circulator, wherein at least a portion of the light beam is directed by the second port of the circulator into the birefringent fiber grating of the optical fiber, the birefringent fiber grating at least partially reflects the light beam back to the circulator where the light beam is directed by the output port of the circulator through a polarizer and onto a spectrometer.

72. The method of claim 68, wherein light beam director is a fused biconical taper.

73. The method of claim 68, wherein the optical fiber is low birefringence optical fiber and the birefringent grating is written onto the optical fiber.

74. The method of claim 68, further comprising sensing twist of an elongate member of a surgical system wherein the optical fiber extends along an axis of the elongate member.

75. The method of claim 68, wherein the elongate member is manually or robotically controlled.

76. A shape measuring system comprising:

an optical fiber having birefringent axes;

a first fiber grating written on the optical fiber such that two effective fiber gratings are established one on each of the birefringent axes to measure bend.

77. A shape measuring system of claim 76, wherein the optical fiber has an index of refraction gradient across each of the birefringent axes.

78. A shape measuring system of claim 77, wherein the index of refraction gradient is induced by exposure to light.

79. A shape measuring system of claim 76, wherein a second fiber grating is a tilted or angled fiber grating written on the optical fiber, the second fiber grating allowing for the measurement of twist.

80. A shape measuring system of claim 79, wherein the titled fiber grating is written on an axis other than the birefringent axes.

81. A shape measuring system of claim 79, wherein the titled fiber grating is written on the optical fiber at a wavelength that differs from the wavelength of the first fiber grating.

82. A shape measuring system according to claim 76, wherein the first fiber grating is an angled or tilted fiber grating to support twist measurements.

83. The shape measuring system of claim 76, wherein the optical fiber extends along an axis of an elongate member of a surgical system for sensing the bend and/or twist of the elongate member.

84. The shape system of claim 83, wherein the elongate member is manually or robotically controlled.

85. A method of sensing a shape of an optical fiber comprising:

detecting bend or twist of an optical fiber having a fiber grating written thereon by measuring a property of a reflection of light from the fiber grating.

86. The method of claim 85, wherein the bend of an optical fiber may be determined by measuring a spectral profile of the reflection from the fiber grating.

87. The method of claim 85, wherein twist is detected by measuring a polarization state of light reflected from the fiber grating written on the optical fiber.

88. The method of claim 85, further comprising drawing down and heating three or more optical fibers to establish a bonded region wherein the surfaces of the fibers are bonded for strain transfer between the fibers and writing the fiber grating on each of the optical fibers along the bonded region.

89. The method of claim 88, wherein a plurality of fiber gratings of different wavelengths are written into the bonded region.

90. The method of claim 88, wherein the bonded region has a cleaved end.

91. The method of claim 85, wherein the fiber grating is a birefringent fiber grating that supports twist measurements.

92. The method of claim 85, wherein the fiber grating is an angled or tilted fiber grating to support twist measurements.

93. The method of claim 85, wherein the optical fibers are polarization preserving optical fibers.

94. The method of claim 85, wherein the optical fiber is a large core optical fiber having a fiber grating written onto a core of the optical fiber;

95. The method of claim 94, wherein an effective period or spacing of the fiber grating varies across the core of the optical fiber.

96. The method of claim 94, wherein the optical fiber has an index of refraction gradient across its core.

97. The method of claim 85, further comprising:

sensing a shape of an elongate member of a surgical system to facilitate navigation of the elongate member in a subject'"'"'s body comprising;

positioning the optical fiber along an axis of the elongate member; and

detecting bend or twist of the elongate member by measuring a property of a reflection of light from the fiber grating.

98. The method of claim 97, wherein three optical fibers are positioned along an axis of the elongate member, wherein the fibers have a bonded region and each of the optical fibers has a fiber grating located on each of the optical fibers along the bonded region.

99. The method of claim 97, wherein the optical fiber has a cleaved end positioned at the distal end of the elongate member.