Optical apparatus which uses a virtually imaged phased array to produce chromatic dispersion

• US 20020093748A1
• Filed: 12/19/2001
• Published: 07/18/2002
• Est. Priority Date: 05/23/2000
• Status: Active Grant

• Current Assignee: II-VI Incorporated
• Original Assignee: Fujitsu Limited
• Inventors: Shirasaki, Masataka, Cao, Simon Xiaofan
• Granted Patent: US 6,481,861 B2
• Time in Patent Office: Days
• US Class Current: 359/868
• CPC Class Codes: G02B 27/0087 Phased arrays
• CPC Class Codes: G02B 27/1006 for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 27/106 for splitting or combining a plurality of identical beams or images, e.g. image replication
• CPC Class Codes: G02B 27/1073 characterized by manufacturing or alignment methods
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/126 The splitting element being a prism or prismatic array, including systems based on total internal reflection
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 27/147 using averaging effects by spatially variable reflectivity on a microscopic level, e.g. polka dots, chequered or discontinuous patterns, or rapidly moving surfaces G02B27/1086 takes precedence
• CPC Class Codes: G02B 27/148 including stacked surfaces having at least one double-pass partially reflecting surface
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/29311 Diffractive element operating in transmission
• CPC Class Codes: G02B 6/29358 Multiple beam interferometer external to a light guide, e.g. Fabry-Pérot, etalon, VIPA plate, OTDL plate, continuous interferometer, parallel plate resonator G02B6/29347, G02B6/29349, G02B6/2935, G02B6/29361 take precedence; resonator evanescently coupled to light guide G02B6/29335
• CPC Class Codes: G02B 6/29361 Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
• CPC Class Codes: G02B 6/29392 Controlling dispersion G02B6/02214 takes precedence; modal dispersion control G02B6/268
• CPC Class Codes: G02B 6/29394 Compensating wavelength dispersion G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: H04B 10/25133 including a lumped electrical or optical dispersion compensator H04B10/2519, H04B10/2525 takes precedence

Abstract

Various configurations of a virtually imaged phased array (VIPA) generator in combination with a mirror to compensate for chromatic dispersion. A VIPA generator produces a light traveling from the VIPA generator. In some embodiments, a variable curvature mirror is positioned to reflect the light back to the VIPA generator. A rotation axis around which the mirror is rotated and a translation path for the rotation axis are provided, to change the curvature of the mirror where the output light is reflected. In other embodiments, a plurality of mirrors have different surface curvatures. A holder has a rotation axis and holds the plurality of mirrors equidistantly from the rotation axis. The holder is rotatable around the rotation axis to bring a different, respective mirror in position to reflect light produced by a VIPA generator back to the VIPA generator. In other embodiments, a rotating mirror is rotatable about a rotation axis to reflect light produced by a VIPA generator to a respective fixed mirror. In still other embodiments, an off-axis parabolic mirror is rotatable about a rotation axis to reflect light produced by a VIPA generator to a respective fixed mirror.

Claims

1. An apparatus comprising:

a variable curvature mirror positioned to reflect light produced by a virtually imaged phased array (VIPA) generator back to the VIPA generator; and

a rotation axis around which the mirror is rotated to change the curvature of the mirror where the output light is reflected.

2. An apparatus as in claim 1, wherein the curvature of the mirror changes along a direction parallel to an angular dispersion direction of the VIPA generator.

3. An apparatus as in claim 1, wherein the rotation axis is perpendicular to an angular dispersion direction of the VIPA generator.

4. An apparatus as in claim 2, wherein the rotation axis is perpendicular to the angular dispersion direction of the VIPA generator.

5. An apparatus as in claim 1, wherein the rotation axis is disposed on or within the mirror.

6. An apparatus as in claim 2, wherein the rotation axis is disposed on or within the mirror.

7. An apparatus as in claim 3, wherein the rotation axis is disposed on or within the mirror.

8. An apparatus as in claim 1, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

9. An apparatus as in claim 2, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

10. An apparatus as in claim 3, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

11. An apparatus as in claim 1, wherein the curvature of the mirror varies from a flat portion to a convex portion.

12. An apparatus as in claim 2, wherein the curvature of the mirror varies from a flat portion to a convex portion.

13. An apparatus as in claim 3, wherein the curvature of the mirror varies from a flat portion to a convex portion.

14. An apparatus as in claim 5, wherein the curvature of the mirror varies from a flat portion to a convex portion.

15. An apparatus as in claim 8, wherein the curvature of the mirror varies from a flat portion to a convex portion.

17. An apparatus as in claim 16, wherein the curvature of the mirror changes along a direction parallel to an angular dispersion direction of the VIPA generator.

18. An apparatus as in claim 16, wherein the rotation axis is perpendicular to an angular dispersion direction of the VIPA generator.

19. An apparatus as in claim 17, wherein the rotation axis is perpendicular to the angular dispersion direction of the VIPA generator.

20. An apparatus as in claim 16, wherein the rotation axis is disposed on or within the mirror.

21. An apparatus as in claim 17, wherein the rotation axis is disposed on or within the mirror.

22. An apparatus as in claim 18, wherein the rotation axis is disposed on or within the mirror.

23. An apparatus as in claim 16, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

24. An apparatus as in claim 17, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

25. An apparatus as in claim 18, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

26. An apparatus as in claim 16, where in t he curvature of the mirror varies from a flat portion to a convex portion.

27. An apparatus as in claim 17, wherein the curvature of the mirror varies from a flat portion to a convex portion.

28. An apparatus as in claim 18, wherein the curvature of the mirror varies from a flat portion to a convex portion.

29. An apparatus as in claim 20, wherein the curvature of the mirror varies from a flat portion to a convex portion.

30. An apparatus as in claim 23, wherein the curvature of the mirror varies from a flat portion to a convex portion.

31. An apparatus as in claim 16, further comprising:

a lens directing the light traveling from the VIPA generator to the mirror so that the mirror reflects the light, the reflected light being directed by the lens back to the VIPA generator.

32. An apparatus as in claim 23, further comprising:

a lens directing the light traveling from the VIPA generator to the mirror so that the mirror reflects the light, the reflected light being directed by the lens back to the VIPA generator.

16. An apparatus comprising:

a virtually imaged phased array (VIPA) generator producing a light traveling from the VIPA generator;

a variable curvature mirror positioned to reflect the light back to the VIPA generator; and

a rotation axis around which the mirror is rotated to change the curvature of the mirror where the output light is reflected.

33. An apparatus comprising:

a virtually imaged phased array (VIPA) generator receiving an input light at a respective wavelength and producing a corresponding output light traveling from the VIPA generator in a direction determined by the wavelength of the input light;

a variable curvature mirror positioned to reflect the output light back to the VIPA generator so that the reflected output light travels through the VIPA generator, to thereby provide dispersion compensation to the input light; and

a rotation axis around which the mirror is rotated to change the curvature of the mirror where the output light is reflected, to thereby vary an amount of dispersion compensation provided to the input light.

34. An apparatus as in claim 33, wherein the curvature of the mirror changes along a direction parallel to an angular dispersion direction of the VIPA generator.

35. An apparatus as in claim 33, wherein the rotation axis is perpendicular to an angular dispersion direction of the VIPA generator.

36. An apparatus as in claim 34, wherein the rotation axis is perpendicular to the angular dispersion direction of the VIPA generator.

37. An apparatus as in claim 33, wherein the rotation axis is disposed on or within the mirror.

38. An apparatus as in claim 33, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

39. An apparatus as in claim 35, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

40. An apparatus as in claim 33, wherein the curvature of the mirror varies from a flat portion to a convex portion.

41. An apparatus as in claim 33, further comprising:

a lens directing the output light traveling from the VIPA generator to the mirror so that the mirror reflects the output light, the reflected light being directed by the lens back to the VIPA generator.

42. An apparatus as in claim 38, further comprising:

a lens directing the output light traveling from the VIPA generator to the mirror so that the mirror reflects the output light, the reflected light being directed by the lens back to the VIPA generator.

43. An apparatus comprising:

a radiation window;

first and second reflecting surfaces in parallel with each other, the first reflecting surface allowing substantially no light to be transmitted therethrough and being in the same plane as the radiation window, the second reflecting surface having a reflectivity which causes a portion of light incident thereon to be transmitted therethrough, wherein

an input light at a respective wavelength travels through the radiation window and is focused into a line, and

the first and second reflecting surfaces are positioned so that the input light radiates from the line to be reflected a plurality of times between the first and second reflecting surfaces and thereby cause a plurality of lights to be transmitted through the second reflecting surface, the plurality of transmitted lights interfering with each other to produce a collimated output light which travels from the second reflecting surface along a direction determined by the wavelength of the input light, and is thereby specially distinguishable from an output light formed for an input light having a different wavelength;

a variable curvature mirror reflecting the output light back to the second reflecting surface to pass through the second reflecting surface and undergo multiple reflection between the first and second reflecting surfaces; and

a rotation axis around which the mirror is rotated to change the curvature of the mirror where the output light is reflected.

44. An apparatus as in claim 43, wherein the curvature of the mirror changes along a direction parallel to a plane which includes the travel direction of collimated output light from the second reflecting surface for input light at different wavelengths.

45. An apparatus as in claim 43, wherein the rotation axis is perpendicular to a plane which includes the travel direction of collimated output light from the second reflecting surface for input light at different wavelengths.

46. An apparatus as in claim 43, wherein the rotation axis is disposed on or within the mirror.

47. An apparatus as in claim 43, further comprising a translation path along which the rotation axis is movable to thereby provide both rotation and translation to change the curvature of the mirror where the output light is reflected.

48. An apparatus as in claim 43, wherein the curvature of the mirror varies from a flat portion to a convex portion.

49. An apparatus as in claim 43, further comprising:

a lens directing the output light traveling from the second reflecting surface to the mirror so that the mirror reflects the output light, the reflected light being directed by the lens back to the second reflecting surface.

50. An apparatus comprising:

a plurality of mirrors having different surface curvatures to reflect light; and

a holder having a rotation axis and holding the plurality of mirrors equidistantly from the rotation axis, the holder being rotatable around the rotation axis to bring a different, respective mirror of the plurality of mirrors in position to reflect light produced by a virtually imaged phased array (VIPA) generator back to the VIPA generator.

51. An apparatus as in claim 50, wherein the plurality of mirrors are separate, non-contiguous mirrors.

52. An apparatus as in claim 50, wherein the plurality of mirrors are portions of a single mirror surface of continuously varying curvature.

53. An apparatus comprising:

a virtually imaged phased array (VIPA) generator producing light;

a plurality of mirrors having different surface curvatures; and

a holder having a rotation axis and holding the plurality of mirrors equidistantly from the rotation axis, the holder being rotatable around the rotation axis to bring a different, respective mirror of the plurality of mirrors in position to reflect the light produced by a VIPA generator back to the VIPA generator.

54. An apparatus as in claim 53, wherein the plurality of mirrors are separate, non-contiguous mirrors.

55. An apparatus as in claim 53, wherein the plurality of mirrors are portions of a single mirror surface of continuously varying curvature.

56. An apparatus as in claim 53, further comprising:

a lens focusing the light produced by the VIPA generator to the respective mirror in position to reflect the light, and directing the reflected light back to the VIPA generator.

58. An apparatus as in claim 57, wherein the plurality of mirrors are separate, non-contiguous mirrors.

59. An apparatus as in claim 57, wherein the plurality of mirrors are portions of a single mirror surface of continuously varying curvature.

60. An apparatus as in claim 57, further comprising:

a lens focusing the output light traveling from the VIPA generator to the respective mirror in position to reflect the light, and directing the reflected light back to the VIPA generator.

57. An apparatus comprising:

a virtually imaged phased array (VIPA) generator receiving an input light at a respective wavelength and producing a corresponding output light traveling from the VIPA generator in a direction determined by the wavelength of the input light;

a plurality of mirrors having different surface curvatures; and

a holder having a rotation axis and holding the plurality of mirrors equidistantly from the rotation axis, the holder being rotatable around the rotation axis to bring a different, respective mirror of the plurality of mirrors in position to reflect the output light back to the VIPA generator, to thereby provide dispersion compensation to the input light.

61. An apparatus comprising:

a radiation window;

first and second reflecting surfaces in parallel with each other, the first reflecting surface allowing substantially no light to be transmitted therethrough and being in the same plane as the radiation window, the second reflecting surface having a reflectivity which causes a portion of light incident thereon to be transmitted therethrough, wherein

an input light at a respective wavelength travels through the radiation window and is focused into a line, and

the first and second reflecting surfaces are positioned so that the input light radiates from the line to be reflected a plurality of times between the first and second reflecting surfaces and thereby cause a plurality of lights to be transmitted through the second reflecting surface, the plurality of transmitted lights interfering with each other to produce a collimated output light which travels from the second reflecting surface along a direction determined by the wavelength of the input light, and is thereby specially distinguishable from an output light formed for an input light having a different wavelength;

a plurality of mirrors having different surface curvatures; and

a holder having a rotation axis and holding the plurality of mirrors equidistantly from the rotation axis, the holder being rotatable around the rotation axis to bring a different, respective mirror of the plurality of mirrors in position to reflect the output light back to the second reflecting surface to pass through the second reflecting surface and undergo multiple reflection between the first and second surfaces.

62. An apparatus as in claim 61, wherein the plurality of mirrors are separate, non-contiguous mirrors.

63. An apparatus as in claim 61, wherein the plurality of mirrors are portions of a single mirror surface of continuously varying curvature.

64. An apparatus as in claim 61, further comprising:

a lens focusing the output light traveling from the second reflecting surface to the respective mirror in position to reflect the output light, and directing the reflected light back to the second reflecting surface.

65. An apparatus comprising:

a plurality of fixed mirrors having different surface curvatures to reflect light; and

a rotating mirror rotatable about a rotation axis to reflect light produced by a virtually imaged phased array (VIPA) generator to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the VIPA generator.

66. An apparatus as in claim 65, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

67. An apparatus as in claim 65, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

69. An apparatus as in claim 68, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

70. An apparatus as in claim 68, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

71. An apparatus as in claim 68, further comprising:

a lens directing the light produced by the VIPA generator to rotating mirror, and directing the light from the fixed mirror and reflected by the rotating mirror back to the VIPA generator.

68. An apparatus comprising:

a virtually imaged phased array (VIPA) generator producing light;

a plurality of fixed mirrors having different surface curvatures to reflect light; and

a rotating mirror rotatable about a rotation axis to reflect light produced by the VIPA generator to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the VIPA generator.

72. An apparatus comprising:

a virtually imaged phased array (VIPA) generator receiving an input light at a respective wavelength and producing a corresponding output light traveling from the VIPA generator in a direction determined by the wavelength of the input light;

a plurality of fixed mirrors having different surface curvatures to reflect light; and

a rotating mirror rotatable about a rotation axis to reflect the output light traveling from the VIPA generator to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the VIPA generator, to thereby provide dispersion compensation to the input light.

73. An apparatus as in claim 72, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

74. An apparatus as in claim 72, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

75. An apparatus as in claim 72, further comprising:

a lens focusing the output light traveling from the VIPA generator to the rotating mirror, and directing the light from the fixed mirror and reflected by the rotating mirror back to the VIPA generator.

76. An apparatus comprising:

a radiation window;

first and second reflecting surfaces in parallel with each other, the first reflecting surface allowing substantially no light to be transmitted therethrough and being in the same plane as the radiation window, the second reflecting surface having a reflectivity which causes a portion of light incident thereon to be transmitted therethrough, wherein

an input light at a respective wavelength travels through the radiation window and is focused into a line, and

the first and second reflecting surfaces are positioned so that the input light radiates from the line to be reflected a plurality of times between the first and second reflecting surfaces and thereby cause a plurality of lights to be transmitted through the second reflecting surface, the plurality of transmitted lights interfering with each other to produce a collimated output light which travels from the second reflecting surface along a direction determined by the wavelength of the input light, and is thereby specially distinguishable from an output light formed for an input light having a different wavelength;

a plurality of fixed mirrors having different surface curvatures to reflect light; and

a rotating mirror rotatable about a rotation axis to reflect the output light traveling from the second reflecting surface to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the second reflecting surface to pass through the second reflecting surface and undergo multiple reflection between the first and second reflecting surfaces.

77. An apparatus as in claim 76, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

78. An apparatus as in claim 76, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

79. An apparatus as in claim 76, further comprising:

a lens focusing the output light traveling from the second reflecting surface to the rotating mirror, and directing the light from the fixed mirror and reflected by the rotating mirror back to the second reflecting surface.

80. An apparatus comprising:

a plurality of fixed mirrors having different surface curvatures to reflect light; and

an off-axis parabolic mirror rotatable about a rotation axis to reflect light produced by a virtually imaged phased array (VIPA) generator to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the VIPA generator.

81. An apparatus as in claim 80, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

82. An apparatus as in claim 80, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

83. An apparatus comprising:

a virtually imaged phased array (VIPA) generator producing light;

a plurality of fixed mirrors having different surface curvatures to reflect light; and

an off-axis parabolic mirror rotatable about a rotation axis to reflect light produced by the VIPA generator to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the VIPA generator.

84. An apparatus as in claim 83, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

85. An apparatus as in claim 83, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

86. An apparatus comprising:

a virtually imaged phased array (VIPA) generator receiving an input light at a respective wavelength and producing a corresponding output light traveling from the VIPA generator in a direction determined by the wavelength of the input light;

a plurality of fixed mirrors having different surface curvatures to reflect light; and

an off-axis parabolic mirror rotatable about a rotation axis to reflect the output light traveling from the VIPA generator to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the VIPA generator, to thereby provide dispersion compensation to the input light.

87. An apparatus as in claim 86, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

88. An apparatus as in claim 86, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

90. An apparatus as in claim 89, wherein the plurality of fixed mirrors are separate, non-contiguous mirrors.

91. An apparatus as in claim 89, wherein the plurality of fixed mirrors are portions of a single mirror surface of continuously varying curvature.

89. An apparatus comprising:

a radiation window;

first and second reflecting surfaces in parallel with each other, the first reflecting surface allowing substantially no light to be transmitted therethrough and being in the same plane as the radiation window, the second reflecting surface having a reflectivity which causes a portion of light incident thereon to be transmitted therethrough, wherein

an input light at a respective wavelength travels through the radiation window and is focused into a line, and

the first and second reflecting surfaces are positioned so that the input light radiates from the line to be reflected a plurality of times between the first and second reflecting surfaces and thereby cause a plurality of lights to be transmitted through the second reflecting surface, the plurality of transmitted lights interfering with each other to produce a collimated output light which travels from the second reflecting surface along a direction determined by the wavelength of the input light, and is thereby specially distinguishable from an output light formed for an input light having a different wavelength;

a plurality of fixed mirrors having different surface curvatures to reflect light; and

an off-axis parabolic mirror rotatable about a rotation axis to reflect the output light traveling from the second reflecting surface to a respective fixed mirror of the plurality of fixed mirrors, and to reflect the light reflected by the respective fixed mirror back to the second reflecting surface to pass through the second reflecting surface and undergo multiple reflection between the first and second reflecting surfaces.