Optoelectronic fiber photodetector

• US 20070019917A1
• Filed: 07/01/2005
• Published: 01/25/2007
• Est. Priority Date: 07/14/2003
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Joannopoulos, John D., Shapira, Ofer, Fink, Yoel, Abouraddy, Ayman F., Bayindir, Mehmet, Sorin, Fabien, Hinczewski, Dursen Saygin, Viens, Jean F., Arnold, Jerimy
• Granted Patent: US 7,292,758 B2
• Time in Patent Office: Days
• US Class Current: 385/123
• CPC Class Codes: C03B 37/026 Drawing fibres reinforced with a metal wire or with other non-glass material
• CPC Class Codes: G01J 2003/1213 Filters in general, e.g. dichroic, band
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: H01L 27/1446 in a repetitive configuration
• CPC Class Codes: H01L 27/14601 Structural or functional details thereof
• CPC Class Codes: H01L 31/035281 Shape of the body
• CPC Class Codes: H01L 31/09 Devices sensitive to infrared, visible or ultraviolet radiation H01L31/101 takes precedence
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

The invention provides an optical fiber photodetector including a photoconductive element, such as a semiconducting element, having a fiber length. The semiconducting element is characterized as a non-composite material in at least one fiber direction. At least one pair of conducting electrodes is in contact with the semiconducting element along the fiber length, and an insulator is provided along the fiber length. An optical resonator can be disposed along the fiber length and along a path of illumination to the semiconducting element. The resonator is dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element. The fiber photodetector can be arranged in a photodetecting fiber grid, photodetecting fiber fabric, or other configuration for detecting incident illumination.

Claims

1. A fiber photodetector comprising:

A semiconducting element having a fiber length and being characterized as a non-composite material in at least one fiber direction;

at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length; and

an insulator along the fiber length.

2. The fiber photodetector of claim 1 wherein the semiconducting element is characterized as a non-composite material along a circumferential fiber direction.

3. The fiber photodetector of claim 1 wherein the semiconducting element is characterized as a non-composite material along an axial fiber direction.

22. The fiber photodetector of claim 1 wherein the semiconducting element comprises a solid semiconducting rod.

23. The fiber photodetector of claim 1 wherein the semiconducting element comprises a hollow semiconducting rod.

24. The fiber photodetector of claim 1 wherein the semiconducting element comprises a bulk semiconducting element.

25. The fiber photodetector of claim 1 wherein the semiconducting element comprises a solid semiconducting fiber core.

26. The fiber photodetector of claim 1 wherein the semiconducting element comprises a hollow semiconducting fiber core.

27. The fiber photodetector of claim 1 wherein the semiconducting element comprises a semiconducting layer.

28. The fiber photodetector of claim 1 wherein the semiconducting element comprises a circumferential semiconducting layer.

29. The fiber photodetector of claim 1 wherein the semiconducting element comprises a plurality of semiconducting elements, each semiconducting element in contact with at least one pair of conducting electrodes along the fiber length.

30. The fiber photodetector of claim 29 wherein the plurality of semiconducting elements comprise concentric circumferential layers of semiconducting elements each separated by an insulator.

31. The fiber photodetector of claim 29 wherein the plurality of semiconducting elements comprise bulk semiconducting elements disposed across a fiber cross section.

32. The fiber photodetector of claim 1 wherein the semiconducting element comprises a semiconducting chalcogenide glass.

36. The fiber photodetector of claim 1 wherein the insulator comprises a polymeric insulating material.

42. The fiber photodetector of claim 1 wherein the insulator is a circumferential protective fiber layer disposed at an outer surface of the fiber.

43. The fiber photodetector of claim 1 wherein the insulator is substantially transparent to at least one illumination wavelength.

44. The fiber photodetector of claim 1 wherein the conducting electrodes comprise metal electrodes.

45. The fiber photodetector of claim 1 wherein the conducting electrodes comprise metal alloy electrodes.

46. The fiber photodetector of claim 1 wherein the conducting electrodes comprise Sn electrodes

47. The fiber photodetector of claim 1 wherein the conducting electrodes of each electrode pair are connected in a photodetector circuit to apply a bias voltage to the semiconducting element.

51. The fiber photodetector of claim 1 wherein the at least one pair of conducting electrodes comprises a plurality of pairs of conducting electrodes.

53. The fiber photodetector of claim 1 wherein each conducting electrode is geometrically confined by the semiconducting element and the insulator.

54. The fiber photodetector of claim 1 further comprising an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.

61. The fiber photodetector of claim 1 arranged in a photodetecting fiber grid having a plurality of rows of fiber photodetectors and a plurality of columns of fiber photodetectors, each fiber photodetector including a semiconducting element having a fiber length and being continuous along at least one fiber direction, at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length, and an insulator along the fiber length;

wherein each fiber photodetector is connected to a sensing circuit for detecting fiber grid coordinates of illumination incident on the fiber grid.

63. The fiber photodetector of claim 1 arranged in a photodetecting fiber fabric having a plurality of fiber photodetectors woven together, each fiber photodetector including a semiconducting element having a fiber length and being continuous along at least one fiber direction, at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length, and an insulator along the fiber length;

wherein each fiber photodetector is connected to a sensing circuit for detecting illumination incident on the fiber fabric.

65. The fiber photodetector of claim 1 wherein photodetection properties characteristic of the fiber photodetector are maintained at an operating temperature of at least about 150°

C. and a duration of at least about 24 hours.

4. A fiber photodetector comprising:

a non-composite photoconductive element having a fiber length;

at least one pair of conducting electrodes in contact with the photoconductive element along the fiber length; and

an insulator along the fiber length.

5. A fiber photodetector comprising:

A non-particulate semiconducting element having a fiber length;

at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length; and

an insulator along the fiber length.

6. A fiber photodetector comprising:

a semiconducting element having a fiber length and being continuous along at least one fiber direction;

at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length; and

an insulator along the fiber length.

7. The fiber photodetector of claim 6 wherein the semiconducting element is continuous along a circumferential fiber direction.

8. The fiber photodetector of claim 6 wherein the semiconducting element is continuous along an axial fiber direction.

9. A fiber photodetector comprising:

an inorganic photoconductive element having a fiber length;

at least one pair of conducting electrodes in contact with the photoconductive element along the fiber length; and

an insulator along the fiber length.

10. The fiber photodetector of claim 9 wherein the photoconductive element comprises a semiconducting element.

11. A fiber photodetector comprising:

A semiconducting element having a fiber length and being homogeneous in it least one fiber direction;

at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length; and

an insulator along the fiber length.

12. The fiber photodetector of claim 11 wherein the semiconducting element is homogeneous along a circumferential fiber direction.

13. The fiber photodetector of claim 11 wherein the semiconducting element is homogeneous along a circumferential fiber direction.

14. A fiber photodetector comprising:

a noncrystalline semiconducting element having a fiber length;

at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length; and

an insulator along the fiber length.

15. The fiber photodetector of claim 14 wherein the semiconducting element is amorphous.

16. The fiber photodetector of claim 14 wherein the semiconducting element is glassy.

17. The fiber photodetector of claim 14 wherein the semiconducting element is characterized by an ability to be crystallized by at least one of optical illumination and elevated temperature.

18. The fiber photodetector of claim 14 wherein the semiconducting element includes glassy regions and crystalline regions.

19. A fiber photodetector comprising:

a semiconducting element having a fiber length and being characterized by a bandgap that is less than about 3 eV;

at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length; and

an insulator along the fiber length.

20. The fiber photodetector of claim 19 wherein the semiconducting element is characterized by a bandgap that is less than about 2.5 eV.

21. The fiber photodetector of claim 20 wherein the semiconducting element is characterized by a bandgap that is less than about 2 eV.

33. The fiber photodetector of claim 33 wherein the chalcogenide glass comprises (As₄₀Se₆₀)_1-xSn_x.

34. The fiber photodetector of claim 33 wherein the chalcogenide glass comprises As₄₀Se₅₀Te₁₀Sn₅.

35. The fiber photodetector of claim 33 wherein the chalcogenide glass comprises As₂Se₃.

37. The fiber photodetector of claim 37 wherein the polymeric insulating material comprises a high glass-transition-temperature material.

38. The fiber photodetector of claim 37 wherein the polymeric insulating material comprises poly-ether imide.

39. The fiber photodetector of claim 37 wherein the polymeric insulating material comprises poly-ether sulfone.

40. The fiber photodetector of claim 37 wherein the polymeric insulating material comprises poly-methyl methacrylate.

41. The fiber photodetector of claim 37 wherein the polymeric insulating material comprises a polymeric layer.

48. The fiber photodetector of claim 48 wherein the photodetector circuit is configured to measure an indication of photogenerated charge produced by the fiber photodetector.

49. The fiber photodetector of claim 49 wherein the photodetector circuit is configured to measure current as an indication of photogenerated charge produced by the fiber photodetector.

50. The fiber photodetector of claim 49 wherein the photodetector circuit is configured to measure capacitance as an indication of photogenerated charge produced by the fiber photodetector.

52. The fiber photodetector of claim 52 wherein the plurality of pairs of conducting electrodes are arranged at selected positions on the semiconducting element and with connections to apply corresponding bias voltages to the semiconducting element for determining incident illumination directionality.

55. The fiber photodetector of claim 55 wherein the optical resonator is disposed along the fiber length concentrically with the semiconducting element.

56. The fiber photodetector of claim 55 wherein the optical resonator comprises a cascade of optical resonators that together substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.

57. The fiber photodetector of claim 55 wherein the optical resonator comprises a resonant cavity bound by dielectric mirror structures.

58. The fiber photodetector of claim 58 wherein the optical resonant cavity comprises an insulator.

59. The fiber photodetector of claim 58 wherein the dielectric mirror structures each comprise alternating layers of a semiconductor and an insulator.

60. The fiber photodetector of claim 58 wherein the thicknesses of the resonant cavity and dielectric mirror structures are dimensioned to transmit a prescribed range of wavelengths around a selected center wavelength.

62. The fiber photodetector of claim 62 wherein at least one fiber photodetector in the fiber grid includes an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.

64. The fiber fabric of claim 64 wherein at least one fiber photodetector in the fiber fabric includes an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.

66. The fiber photodetector of claim 66 wherein photodetection properties characteristic of the fiber photodetector are maintained at an operating temperature of at least about 200°

C. and a duration of at least about 24 hours.

67. A photodetecting fiber grid comprising:

a plurality of rows of fiber photodetectors;

a plurality of columns of fiber photodetectors;

wherein each fiber photodetector includes a semiconducting element having a fiber length, at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length, and an insulator along the fiber length; and

wherein each fiber photodetector is connected to a sensing circuit for detecting coordinates of illumination incident on the fiber grid.

68. The photodetecting fiber grid of claim 68 wherein a number, 2N, of fiber photodetectors are included in the fiber grid and the detected fiber grid illumination coordinates are characterized by a detection resolution of N².

69. The photodetecting fiber grid of claim 68 wherein at least one fiber photodetector in the fiber grid includes an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.

74. The photodetecting fiber grid of claim 68 further comprising a printed circuit board frame to which each grid row and grid column is connected for acquiring photogenerated charge.

75. The photodetecting fiber grid of claim 68 wherein the sensing circuit includes an analog-to-digital converter.

76. The photodetecting fiber grid of claim 68 wherein the sensing circuit includes a signal amplifier.

77. The photodetecting fiber grid of claim 68 wherein the sensing circuit includes a multiplexer connected to multiplex photogenerated charge signals from the fiber grid rows and columns.

78. The photodetecting fiber grid of claim 68 wherein the sensing circuit includes a connection for delivering acquired photogenerated charge signals to a computer.

80. The photodetecting fiber grid of claim 68 wherein the grid is disposed in a substantially transparent medium.

83. The photodetecting fiber grid of claim 68 wherein the grid is disposed adjacent to a computer screen and connected to a computer graphical user interface programmed to control the screen display in response to illumination incident on the fiber grid.

84. The photodetecting fiber grid of claim 68 wherein the grid rows and columns are arranged in a two-dimensional structure.

85. The photodetecting fiber grid of claim 68 wherein the grid rows and columns are arranged in a three-dimensional structure.

88. The photodetecting fiber grid of claim 68 wherein the grid rows and columns are arranged to generally follow surface contours of an object over which the grid is disposed.

70. The photodetecting fiber grid of claim 70 wherein each fiber grid row comprises a plurality of the fiber photodetectors, at least one fiber photodetector in the row including an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.

71. The photodetecting fiber grid of claim 70 wherein each fiber grid column comprises a plurality of the fiber photodetectors, at least one fiber photodetector in the column including an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.

72. The photodetecting fiber grid of claim 71 wherein each fiber photodetector in a fiber grid row includes an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths, substantially distinct to that fiber photodetector, that are transmitted to the semiconducting element.

73. The photodetecting fiber grid of claim 72 wherein each fiber photodetector in a fiber grid column includes an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths, substantially distinct to that fiber photodetector, that are transmitted to the semiconducting element.

79. The photodetecting fiber grid of claim 79 wherein the computer is programmed to compare the acquired photogenerated charge signals and determine a grid row having a maximum charge signal and a grid column having a maximum charge signal, indicating the coordinates of illumination incident on the fiber grid.

81. The photodetecting fiber grid of claim 81 wherein the transparent medium comprises a glass.

82. The photodetecting fiber grid of claim 81 wherein the transparent medium comprises a plastic.

86. The photodetecting fiber grid of claim 86 wherein the three-dimensional structure comprises a sphere.

87. The photodetecting fiber grid of claim 86 wherein the three-dimensional structure comprises a rectangular structure.

89. A photodetecting fiber fabric comprising:

a plurality of fiber photodetectors woven together;

wherein each fiber photodetector includes a semiconducting element having a fiber length, at least one pair of conducting electrodes in contact with the semiconducting element along the fiber length, and an insulator along the fiber length; and

wherein each fiber photodetector is connected to a sensing circuit for detecting illumination incident on the fiber fabric.

90. The photodetecting fiber fabric of claim 90 wherein at least a portion of the plurality of woven fiber photodetectors each includes an optical resonator disposed along the fiber length and along a path of illumination to the semiconducting element, the resonator being dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths, substantially distinct to that fiber photodetector, that are transmitted to the semiconducting element.

91. The photodetecting fiber fabric of claim 90 wherein at least one of the woven fiber photodetectors comprises a hollow-core fiber photodetector.