Micromechanical optical switch

• US 6,611,366 B2
• Filed: 04/22/2002
• Issued: 08/26/2003
• Est. Priority Date: 08/01/2000
• Status: Expired due to Fees

• Current Assignee: Cheetah Omni LLC
• Original Assignee: Cheetah Omni LLC
• Inventors: Islam, Mohammed N., Kuditcher, Amos
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): Spector, David N.
• Application Number:
  US10/131,744
• Publication Number:
  US 20020159129A1
• Time in Patent Office: 491 Days
• Field of Search: 359/139, 359/291, 359/578, 359/583, 359/589, 385/16, 385/47
• US Class Current: 359/291
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/3516 the reflective optical element moving along the beam path, e.g. controllable diffractive effects using multiple micromirrors within the beam
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 6/3594 Characterised by additional functional means, e.g. means for variably attenuating or branching or means for switching differently polarized beams

Abstract

An optical switch element is described, which includes a fixed layer disposed outwardly from a substrate and a movable mirror assembly disposed outwardly from the fixed layer. The moveable mirror assembly is operable to move relative to the fixed layer responsive to a voltage applied to the movable mirror assembly. In a particular embodiment, the movable mirror assembly includes an inner strip spaced apart from the fixed layer by a first distance and an outer strip disposed approximately adjacent to the inner strip and spaced apart from the fixed layer by a second distance which is greater than the first distance. The optical transmission of the optical switch element changes depending on the position of the movable mirror assembly.

Claims

1. An optical communication element, comprising:

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror assembly disposed outwardly from the fixed layer and forming with the fixed layer an optical cavity, the moveable mirror assembly operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror assembly to affect a change in an optical characteristic of the optical cavity;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state at a rate associated with an average size of a packet traversing the communication element.

2. The optical communication element of claim 1, wherein the moveable mirror assembly comprises:

an inner strip spaced apart from the fixed layer by a first distance; and

an outer strip disposed approximately adjacent to the inner strip and spaced apart from the fixed layer by a second distance which is greater than the first distance.

3. The optical communication element of claim 1, wherein the fixed layer comprises a fixed mirror layer and wherein the optical cavity comprises a Fabry-Perot cavity.

4. The optical communication element of claim 1, wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state at a rate optimized for a specified packet size.

5. The optical communication element of claim 1, wherein the rate is faster than once every 10 microseconds.

6. The optical communication element of claim 1, wherein the rate is faster than once every 30 microseconds.

7. The optical communication element of claim 1, wherein the average packet size comprises between 40 and 60 bytes and wherein the rate comprises between once each 300 nanoseconds and once each 100 nanoseconds.

8. The optical communication element of claim 1, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

9. The optical communication element of claim 1, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.

10. An optical communication element, comprising:

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror assembly disposed outwardly from the fixed layer and forming with the fixed layer an optical cavity, the moveable mirror assembly operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror assembly to affect a change in an optical characteristic of the optical cavity;

wherein the optical communication element is operable to change between a substantially reflective state and a less than substantially reflective state at a rate associated with an average size of a packet traversing the communication element.

11. The optical communication element of claim 10, wherein the unitary moveable mirror assembly comprises:

an inner strip spaced apart from the fixed layer by a first distance; and

an outer strip disposed approximately adjacent to the inner strip and spaced apart from the fixed layer by a second distance which is greater than the first distance.

12. An optical communication element, comprising:

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state in response to the applied voltage.

13. The optical communication element of claim 12, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

14. The optical communication element of claim 12, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.

15. An optical communication element, comprising:

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially reflective state and a less than substantially reflective state in response to the applied voltage.

16. The optical communication element of claim 15, wherein the switch between a substantially reflective state and a less than substantially reflective state provides a binary optical switching function.

17. The optical communication element of claim 15, wherein the switch between a substantially reflective state and a less than substantially reflective state provides a variable optical attenuator function.

18. An optical communication element, comprising:

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state in less than 30 microseconds.

19. The optical communication element of claim 18, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

20. The optical communication element of claim 18, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.

21. An optical communication element, comprising:

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially reflective state and a less than substantially reflective state in less than 30 microseconds.

22. The optical communication element of claim 21, wherein the switch between a substantially reflective state and a less than substantially reflective state provides a binary optical switching function.

23. The optical communication element of claim 21, wherein the switch between a substantially reflective state and a less than substantially reflective state provides a variable optical attenuator function.

24. An optical communication element, comprising:

a first layer disposed outwardly from a substrate; and

a unitary mirror structure disposed outwardly from the first layer and forming with the first layer a cavity having an effective depth;

the optical communication element operable to change the effective depth of the cavity in response to receiving a control signal, wherein the change in the effective depth of the cavity facilitates changing a characteristic of the communication element between a substantially transmissive state and a less than substantially transmissive state at a rate associated with an average size of a packet traversing the communication element.

25. The optical communication element of claim 24, wherein the unitary moveable mirror structure comprises:

an inner strip spaced apart from the fixed layer by a first distance; and

an outer strip disposed approximately adjacent to the inner strip and spaced apart from the fixed layer by a second distance which is greater than the first distance.

26. The optical communication element of claim 24, wherein the control signal comprises a voltage.

27. The optical communication element of claim 24, wherein the control signal comprises a change in temperature.

28. The optical communication element of claim 24, wherein the fixed layer comprises a fixed mirror layer and wherein the optical cavity comprises a Fabry-Perot cavity.

29. The optical communication element of claim 24, wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state in less than 30 microseconds.

30. The optical communication element of claim 24, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

31. The optical communication element of claim 24, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.

32. An optical communication device comprising:

a pair of collimating lens each having a central axis and each coupled to a fiber so that the axis of each collimating lens is at least partially offset from the axis of the fiber; and

an optical communication element disposed between the collimating lenses approximately along the central axis of the fiber and spaced from each of the lenses by approximately a focal length of the respective lens, wherein the optical communication element is operable to receive optical signals from one collimating lens and to either transmits those signals to the other collimating lens or to reflect those signals depending on the position of a moveable mirror structure relative to a fixed layer within the communication element;

wherein the optical communication element comprises;

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication device.

33. An optical communication device comprising:

a first optical element operable to receive an optical signal; and

a second optical element operable to receive an optical signal, the second optical element coupled to the first optical element over a first mode, the first and second optical elements coupled to a single mode fiber wherein the first mode at least partially overlaps the mode of the single mode fiber so that optical signals from the first and second optical elements couple to the fiber only when the first and second optical elements are substantially in phase with one another;

wherein at least one of the first and second optical communication elements comprises;

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication device.

34. An optical communication device comprising:

an input operable to receive an optical signal;

a first receiver coupled to a first output;

a second receiver coupled to a second output; and

an optical communication element coupled between the input and the first and second outputs, the optical communication element comprising;

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication device;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state in response to the applied voltage.

35. The optical communication device of claim 34, wherein the optical communication element receives the input signal at a non-normal angle of incidence.

36. An optical communication device comprising:

an input operable to receive an optical signal;

a first receiver coupled to a first output;

a second receiver coupled to a second output; and

an optical communication element coupled between the input and the first and second outputs, the optical communication element comprising;

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the optical communication device;

wherein the optical communication element is operable to change between a substantially reflective state and a less than substantially reflective state in response to the applied voltage.

37. The optical communication device of claim 36, wherein the optical communication element receives the input signal at a non-normal angle of incidence.

38. A fault tolerant network, comprising:

an ingress access node operable to receive an optical signal from a network element external to the fault tolerant network; and

a fault tolerant node operable to receive the optical signal from the ingress access node and to perform a switching operation on the optical signal depending on a voltage applied to an optical communication element within the fault tolerant node, wherein the fault tolerant node allows transmission of the optical signal when no voltage is applied to the communication element and wherein the optical communication element comprises;

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the fault tolerant network;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state in response to the applied voltage.

39. A fault tolerant network, comprising:

an ingress access node operable to receive an optical signal from a network element external to the fault tolerant network; and

a fault tolerant node operable to receive the optical signal from the ingress access node and to perform a switching operation on the optical signal depending on a voltage applied to an optical communication element within the fault tolerant node, wherein the fault tolerant node allows transmission of the optical signal when no voltage is applied to the communication element and wherein the optical communication element comprises;

a fixed layer disposed outwardly from a substrate; and

a unitary movable mirror structure disposed outwardly from the fixed layer and forming with the fixed layer a cavity, the moveable mirror structure operable to move relative to the fixed layer in response to a voltage applied to the moveable mirror structure to affect a change in a characteristic of the fault tolerant network;

wherein the optical communication element is operable to change between a substantially reflective state and a less than substantially reflective state in response to the applied voltage.

40. A method of communicating optical signals, comprising:

receiving an optical signal at an optical communication element having a fixed layer and a unitary moveable mirror structure disposed outwardly from the fixed layer; and

applying a voltage to the optical communication element to change the position of the moveable mirror structure relative to the fixed layer and cause a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state at a rate associated with an average size of a packet traversing the communication element.

41. The method of claim 40, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

42. The method of claim 40, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.

43. A method of communicating optical signals, comprising:

receiving an optical signal at an optical communication element having a fixed layer and a unitary moveable mirror structure disposed outwardly from the fixed layer; and

applying a voltage to the optical communication element to change the position of the moveable mirror structure relative to the fixed layer and cause a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state in response to the applied voltage.

44. The method of claim 43, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

45. The method of claim 43, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.

46. A method of communicating optical signals, comprising:

receiving an optical signal at an optical communication element having a fixed layer and a unitary moveable mirror structure disposed outwardly from the fixed layer; and

applying a voltage to the optical communication element to change the position of the moveable mirror structure relative to the fixed layer and cause a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially reflective state and a less than substantially reflective state in response to the applied voltage.

47. The method of claim 46 wherein the switch between a substantially reflective state and a less than substantially reflective state provides a binary optical switching function.

48. The method of claim 46, wherein the switch between a substantially reflective state and a less than substantially reflective state provides a variable optical attenuator function.

49. A method of communicating optical signals, comprising:

receiving an optical signal at an optical communication element having a fixed layer and a unitary moveable mirror structure disposed outwardly from the fixed layer; and

applying a voltage to the optical communication element to change the position of the moveable mirror structure relative to the fixed layer and cause a change in a characteristic of the optical communication element;

wherein the optical communication element is operable to change between a substantially transmissive state and a less than substantially transmissive state in less than 30 microseconds.

50. A method of communicating optical signals, comprising:

receiving an optical signal at an optical communication element having a fixed layer and a unitary moveable mirror structure disposed outwardly from the first layer and forming with the first layer a cavity having an effective depth; and

applying a voltage to the optical communication element to change the effective depth of the cavity in response to receiving a control signal, wherein the change in the effective depth of the cavity facilitates changing a characteristic of the communication element between a substantially transmissive state and a less than substantially transmissive state at a rate associated with an average size of a packet traversing the communication element.

51. An optical communication element, comprising:

a first layer disposed outwardly from a substrate; and

a unitary mirror structure disposed outwardly from the first layer and forming with the first layer a cavity having an effective depth;

the optical communication element operable to change the effective depth of the cavity in response to receiving a control signal, wherein the change in the effective depth of the cavity facilitates changing a characteristic of the communication element between a substantially transmissive state and a less than substantially transmissive state in response to the control signal.

52. The optical communication element of claim 51, wherein the unitary moveable mirror structure comprises:

an inner strip spaced apart from the fixed layer by a first distance; and

an outer strip disposed approximately adjacent to the inner strip and spaced apart from the fixed layer by a second distance which is greater than the first distance.

53. The optical communication element of claim 51, wherein the control signal comprises a change in temperature.

54. The optical communication element of claim 51, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

55. The optical communication element of claim 51, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.

56. A method of communicating optical signals, comprising:

receiving an optical signal at an optical communication element having a fixed layer and a unitary moveable mirror structure disposed outwardly from the first layer and forming with the first layer a cavity having an effective depth; and

applying a voltage to the optical communication element to change the effective depth of the cavity in response to receiving a control signal, wherein the change in the effective depth of the cavity facilitates changing a characteristic of the communication element between a substantially transmissive state and a less than substantially transmissive state in response to the control signal.

57. The method of claim 56, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a binary optical switching function.

58. The method of claim 56, wherein the switch between a substantially transmissive state and a less than substantially transmissive state provides a variable optical attenuator function.