Reconfigurable optical switch

• US 6,631,222 B1
• Filed: 05/16/2000
• Issued: 10/07/2003
• Est. Priority Date: 05/16/2000
• Status: Expired due to Fees

• Current Assignee: Xtera Communications Incorporated (Xtera Topco Ltd.)
• Original Assignee: Photuris, Inc. (Mahi Networks Incorporated)
• Inventors: Wagener, Jefferson L., Strasser, Thomas Andrew
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): Kang, Juliana K.
• Application Number:
  US09/571,833
• Time in Patent Office: 1,239 Days
• Field of Search: 385/16, 385/17, 385/18, 385/24, 385/31, 385/33, 385/47, 359/131, 359/196, 359/212, 359/127, 359/124
• US Class Current: 385/16
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)

Abstract

An optical switch includes at least one input port for receiving a WDM optical signal having a plurality of wavelength components, at least three output ports, and a plurality of wavelength selective elements each selecting one of the wavelength components from among the plurality of wavelength components. A plurality of optical elements are also provided, each of which are associated with one of the wavelength selective elements. Each of the optical elements direct the selected wavelength component that is selected by its associated selected element to a given one of the output ports independently of every other wavelength component. The given output port is variably selectable from among all the output ports.

Claims

1. An optical switch comprising:

at least one input port for receiving a WDM optical signal having a plurality of wavelength components;

at least three output ports;

a plurality of wavelength selective elements each selecting one of said wavelength components from among the plurality of wavelength components; and

a plurality of optical elements each associated with one of the wavelength selective elements, each of said optical elements directing the selected wavelength component selected by the associated selected element to a given one of the at least three output ports independently of every other wavelength component, said given output port being variably selectable from among the at least three output ports.

2. The optical switch of claim 1 further comprising a free space region disposed between the input port and the wavelength selective elements.

3. The optical switch of claim 2 wherein said free space region comprises an optically transparent substrate having first and second parallel surfaces, said plurality of wavelength selective elements being arranged in first and second arrays extending along the first and second parallel surfaces, respectively.

4. The optical element of claim 3 wherein said first and second arrays are laterally offset with respect to one another.

5. The optical switch of claim 3 wherein said optical element is a MEM mirror tiltable in a plurality of positions such that in each of the positions the MEM mirror reflects the wavelength component incident thereon to a different one of the output ports.

6. The optical element of claim 5 wherein each of said wavelength selective elements arranged in the first array direct the selected wavelength component to another of said wavelength selective elements arranged in the second array.

7. The optical switch of claim 1 wherein said wavelength selective elements are thin film filters each transmitting therethrough a different one of the wavelength components and reflecting the remaining wavelength components.

8. The optical switch of claim 7 further comprising a detector associated with each of the wavelength selected elements for monitoring the wavelength component transmitted therethrough.

9. The optical switch of claim 1 wherein said optical elements are micro-electromechanical (MEM) optical elements.

10. The optical switch of claim 9 wherein said MEM optical elements are MEM mirrors.

11. The optical switch of claim 10 wherein said MEM mirror is tiltable in a plurality of positions such that in each of the positions the MEM mirror reflects the wavelength component incident thereon to a different one of the output ports.

12. The optical switch of claim 1 wherein said optical elements are mirrors that are selectively tiltable in a plurality of positions such that in each of the positions the mirrors reflect the wavelength component incident thereon to a different one of the output ports.

13. The optical switch of claim 12 wherein said mirrors each include a piezoelectric actuator.

14. The optical switch of claim 12 wherein said optical elements each include a pair of mirrors.

15. The optical switch of claim 12 wherein said optical elements each include a tiltable mirror that is also spatially translatable.

16. The optical switch of claim 1 further comprising a pair of collimating lenses disposed between each one of said wavelength selective elements and the optical element associated therewith, each of said optical elements being positioned at a focal point of each lens in its associated collimating lens pair.

17. The optical switch of claim 1 wherein said optical elements each include a pair of collimating lenses and a tiltable mirror.

18. A method for directing at least first and second wavelength components of a WDM signal that includes a plurality of wavelength components from an input port to selected ones of a plurality of output ports, said method comprising the steps of:

(a) demultiplexing the first wavelength component from the WDM signal;

(b) directing the first wavelength component to a given output port;

(c) demultiplexing the second wavelength component from the WDM signal and directing the second wavelength component to one of the output ports selected independently from the given output port, wherein step (c) is performed subsequent to steps (a) and (b), wherein said plurality of output ports includes at least three output ports and wherein step (c) includes the step of directing the second wavelength component to any of said at least three output ports selected independently from the given output port.

19. The method of claim 18 wherein the steps of directing the first and second wavelength components includes the steps of directing the first and second wavelength components through a free space region.

20. The method of claim 19 wherein the first wavelength component is directed through the free space region by a tiltable mirror.

21. The method of claim 20 wherein the tiltable mirror is a MEM mirror.

22. The method of claim 20 wherein said tiltable mirror includes a pair of tiltable mirrors.

23. The method of claim 20 wherein said tiltable mirror includes a piezoelectric actuator.

24. The method of claim 20 further comprising the step of collimating the first wavelength component onto the tiltable mirror.

25. The method of claim 19 wherein the first wavelength component is directed by a spatially translatable mirror.

26. The method of claim 18 wherein the first wavelength component is demultiplexed by a thin film filter having a passband corresponding to the first wavelength component.

27. The method of claim 18 wherein the demultiplexing and directing steps are performed by a plurality of narrow band free space switches.

28. The method of claim 18 wherein the first and second wavelength components are directed to said output ports by a plurality of tunable, wavelength selective couplers.

29. The method of claim 18 wherein said plurality of output ports includes M output ports and the dernultiplexing and directing steps are performed by a demultiplexer, M multiplexers, and a plurality of 1×

M switches coupling said demultiplexer to said M multiplexers, where M>

2.

30. The method of claim 18 further comprising the step of monitoring the first wavelength component after performing the demultiplexing step.

31. An optical switch comprising:

at least one input port for receiving a WDM optical signal having a plurality of wavelength components;

a plurality of output ports;

means for selecting at least one of said wavelength components from among the plurality of wavelength components and directing the at least one selected wavelength component to a given one of the plurality of output ports independently of every other wavelength component, said given output port being variably selectable from among the plurality of output ports, wherein said selecting and directing means comprises a plurality of narrow band free space switches, and wherein said narrow band free space switch includes a thin film filter and a tiltable optical element.

32. The optical switch of claim 31 wherein said narrow band free space switch includes a thin film filter and a pair of tiltable mirrors.

33. The optical switch of claim 31 wherein said narrow band free space switch includes a thin film filter and a tiltable mirror that is also spatially translatable.

34. The optical switch of claim 31 wherein said selecting and directing means comprises a plurality of tunable, wavelength selective couplers.

35. The optical switch of claim 34 wherein said couplers are acoustic wave null couplers.

36. The optical switch of claim 31 wherein said plurality of output ports includes M output ports and said selecting and directing means comprises a demultiplexer, M multiplexers, and a plurality of 1×

M switches coupling said demultiplexer to said M multiplexers, where M>

2.

37. The optical switch of claim 31 further comprising a detector associated with each of the narrow band free space switches.

38. An optical switch comprising:

at least one input port for receiving a WDM optical signal having a plurality of wavelength components;

at least three output ports;

at least one wavelength selective element selecting each of said wavelength components from among the plurality of wavelength components; and

a plurality of optical elements each receiving a distinct one of the wavelength components from the at least one wavelength selective element, each of said optical elements directing the received wavelength component to a given one of the at least three output ports independently of every other wavelength component, said given output port being variably selectable from among the at least three output ports.

39. The optical switch of claim 38 further comprising a free space region disposed between the input port and said at least one wavelength selective element.

40. The optical switch of claim 39 wherein said free space region comprises an optically transparent substrate having first and second parallel surfaces and said at least one wavelength selective element comprises a plurality of wavelength selective elements, said plurality of wavelength selective elements being arranged in first and second arrays extending along the first and second parallel surfaces, respectively.

41. The optical element of claim 40 wherein said first and second arrays are laterally offset with respect to one another.

42. The optical switch of claim 40 wherein said optical element is a MEM mirror tiltable in a plurality of positions such that in each of the positions the MEM mirror reflects the wavelength component incident thereon to a different one of the output ports.

43. The optical element of claim 42 wherein each of said wavelength selective elements arranged in the first array direct the selected wavelength component to another of said wavelength selective elements arranged in the second array.

44. The optical switch of claim 38 wherein said at least one wavelength selective element comprises a plurality of thin film filters each transmitting therethrough a different one of the wavelength components and reflecting the remaining wavelength components.

45. The optical switch of claim 38 wherein said optical elements are micro-electromechanical (MEM) optical elements.

46. The optical switch of claim 45 wherein said MEM optical elements are MEM mirrors.

47. The optical switch of claim 46 wherein said MEM mirror is tiltable in a plurality of positions such that in each of the positions the MEM mirror reflects the wavelength component incident thereon to a different one of the output ports.

48. The optical switch of claim 38 wherein said optical elements are mirrors that are selectively tiltable in a plurality of positions such that in each of the positions the mirrors reflect the wavelength component incident thereon to a different one of the output ports.

49. The optical switch of claim 48 wherein said mirrors each include a piezoelectric actuator.

50. The optical switch of claim 48 wherein said optical elements each include a pair of mirrors.

51. The optical switch of claim 48 wherein said optical elements each include a tiltable mirror that is also spatially translatable.

52. The optical switch of claim 38 wherein said optical elements each include a collimating lens and a tiltable mirror.

53. An optical switch comprising.

at least one input port for receiving a WDM signal having N wavelength components, where N is an integer ≧

2;

M output ports where M is an integer ≧

3; and

N narrow band, free space switches, wherein for each switch i, where i is an integer from 1 to N, said ith switch selects the ith wavelength component and directs said ith component to a given one of the output ports independently of the output ports to which all of the remaining (N−

1) switches direct their respectively selected wavelength components, and wherein said ith switch selects and directs the ith wavelength component regardless of the input port at which said ith wavelength component is received.

54. The optical switch of claim 53 wherein the N switches collectively include at least one wavelength selective element that selects each of the N wavelength components.

55. The optical switch of claim 54 wherein each of the N switches include an optical element that directs the wavelength component received from the at least one wavelength selective element to a given one of the output ports.

56. The optical switch of claim 53 wherein each of said narrow band free space switches includes a thin film filter and a tiltable optical element.

57. The optical switch of claim 53 wherein each of said narrow band free space switches includes a thin film filter and a pair of tiltable mirrors.

58. The optical switch of claim 53 wherein each of said narrow band free space switches includes a thin film filter and a tiltable mirror that is also spatially translatable.

59. The optical switch of claim 53 further comprising a detector associated with each of the narrow band free space switches.

60. An optical switch comprising:

at least one input port for receiving a WDM optical signal having a plurality of wavelength components;

at least three output ports;

a plurality of wavelength selective elements being arranged so that a first of said wavelength selective elements selects a first wavelength component from among the plurality of wavelength components before a second of said wavelength selective elements selects a second wavelength component from among the plurality of wavelength components; and

a plurality of optical elements each associated with one of the wavelength selective elements, each of said optical elements directing the selected wavelength component selected by the associated wavelength selective element to a given one of the at least three output ports independently of every other wavelength component, said given output port being variably selectable from among the at least three output ports, wherein a first of said optical elements associated with the first wavelength selective element is arranged to direct the selected wavelength component to the given output port before said second of the wavelength selective elements selects the second wavelength component from among the plurality of wavelength components.

61. The optical switch of claim 60 further comprising a free space region disposed between the input port and the wavelength selective elements.

62. The optical switch of claim 61 wherein said free space region comprises an optically transparent substrate having first and second parallel surfaces, said plurality of wavelength selective elements being arranged in first and second arrays extending along the first and second parallel surfaces, respectively.

63. The optical element of claim 62 wherein said first and second arrays are laterally offset with respect to one another.

64. The optical switch of claim 62 wherein said optical element is a MEM mirror tiltable in a plurality of positions such that in each of the positions the MEM mirror reflects the wavelength component incident thereon to a different one of the output ports.

65. The optical element of claim 64 wherein each of said wavelength selective elements arranged in the first array direct the selected wavelength component to another of said wavelength selective elements arranged in the second array.

66. The optical switch of claim 60 wherein said wavelength selective elements are thin film filters each transmitting therethrough a different one of the wavelength components and reflecting the remaining wavelength components.

67. The optical switch of claim 60 wherein said optical elements are micro-electromechanical (MEM) optical elements.

68. The optical switch of claim 67 wherein said MEM optical elements are MEM mirrors.

69. The optical switch of claim 68 wherein said MEM mirror is tiltable in a plurality of positions such that in each of the positions the MEM mirror reflects the wavelength component incident thereon to a different one of the output ports.

70. The optical switch of claim 60 wherein said optical elements are mirrors that are selectively tiltable in a plurality of positions such that in each of the positions the mirrors reflect the wavelength component incident thereon to a different one of the output ports.

71. The optical switch of claim 70 wherein said mirrors each include a piezoelectric actuator.

72. The optical switch of claim 70 wherein said optical elements each include a pair of mirrors.

73. The optical switch of claim 70 wherein said optical elements each include a tiltable mirror that is also spatially translatable.

74. The optical switch of claim 60 further comprising a pair of collimating lenses disposed between each one of said wavelength selective elements and the optical element associated therewith, each of said optical elements being positioned at a focal point of each lens in its associated collimating lens pair.

75. The optical switch of claim 60 wherein said optical elements each include a plurality of collimating lenses and a tiltable mirror.

76. A method for directing at least first and second wavelength components of a WDM signal that includes a plurality of wavelength components from an input port to selected ones of at least three output ports, said method comprising the steps of:

(a) demultiplexing the first wavelength component from the WDM signal;

(b) directing the first wavelength component to a given output port;

(c) demultiplexing the second wavelength component from the WDM signal; and

(d) directing the second wavelength components to any selected one of the at least three output ports selected independently from the given output port.

77. The method of claim 76 wherein steps (c) and (d) are performed subsequent to steps (a) and (b).

78. The method of claim 76 wherein the steps of directing the fist and second wavelength components includes the steps of directing the first and second wavelength components through a free space region.

79. The method of claim 78 wherein the first wavelength component is directed through the free space region by a tiltable mirror.

80. The method of claim 79 wherein the tiltable mirror is a MEM mirror.

81. The method of claim 79 wherein said tiltable mirror includes a pair of tiltable mirrors.

82. The method of claim 79 wherein said tiltable mirror includes a piezoelectric actuator.

83. The method of claim 79 further comprising the step of collimating the first wavelength component onto the tiltable mirror.

84. The method of claim 78 wherein the first wavelength component is directed by a spatially translatable mirror.

85. The method of claim 76 wherein the first wavelength is demultiplexed by a thin film filter having a passband corresponding to the first wavelength.

86. The method of claim 76 wherein the demultiplexing and directing steps are performed by a plurality of narrow band free space switches.

87. The method of claim 76 wherein the demultiplexing and directing steps are performed by a plurality of tunable, wavelength selective couplers.

88. The method of claim 76 wherein said at least three output ports includes N output ports and the demultiplexing and directing steps are performed by a demultiplexer, N multiplexers, and a plurality of 1×

M switches coupling said demultiplexer to said N multiplexers, where M>

1.