Variable blazed grating based signal processing

• US 6,721,473 B1
• Filed: 02/02/2001
• Issued: 04/13/2004
• Est. Priority Date: 02/02/2001
• Status: Expired due to Fees

• Current Assignee: Cheetah Omni LLC
• Original Assignee: Cheetah Omni LLC
• Inventors: Islam, Mohammed N., Kuditcher, Amos
• Primary Examiner(s): Ullah, Akm Enayet
• Assistant Examiner(s): Rahll, Jerry T
• Application Number:
  US09/776,052
• Time in Patent Office: 1,166 Days
• Field of Search: 385/16, 385/18-19, 385/39, 385/47
• US Class Current: 385/18
• CPC Class Codes: G02B 6/2932 comprising a directional router, e.g. directional coupler, circulator
• 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

Abstract

In one aspect of the invention, an optical switching element includes a variable blazed grating operable to receive and reflect one or more input signals while the grating remains in a first position and to receive and diffract one or more input signals while the grating remains in a second position. The switching element further includes a first circulator operable to receive from the variable blazed grating a first output signal traveling approximately along the path of an input signal to the grating but in an approximately opposite direction to that input signal, and to redirect the first output signal from the path of the input signal.

Claims

1. An optical switching element comprising:

a variable blazed grating operable to receive and reflect one or more input signals while the grating remains in a first position and to receive and reflect one or more input signals while the grating remains in a second position, the variable blazed grating comprising;

an inner conductive layer; and

a plurality of approximately adjacent at least partially reflective mirror strips disposed outwardly from the inner conductive layer, each strip operable to receive a portion of an input optical signal, wherein each of the plurality of strips is operable to undergo a partial rotation resulting in a reflection of a majority of the input signal toward an output; and

a first circulator operable to receive from the variable blazed grating a first output signal traveling approximately along the path of an input signal to the grating but in an approximately opposite direction to that input signal, the circulator further operable to redirect the first output signal from the path of the input signal.

2. The optical switching element of claim 1, wherein the first output signal comprises a reflected version of an input signal received by the grating at a normal incident angle to the grating in the first position.

3. The optical switching element of claim 1, wherein the first output signal comprises a reflected version of an input signal received by the grating at a non-normal incident angle to the grating in the first position.

4. The optical switching element of claim 1, wherein the first output signal comprises a majority of reflected portions of an input signal received by the grating at a normal incident angle to the grating in the second position.

5. The optical switching element of claim 1, wherein the first output signal comprises a majority of reflected portions of an input signal received by the grating at a non-normal incident angle to the grating in the second position.

6. The optical switching element of claim 1, further comprising a second circulator operable receive from the variable blazed grating a second output signal traveling approximately along the path of an input signal to the variable blazed grating but in an approximately opposite direction to that input signal, the circulator further operable to redirect the second output signal from the path of the input signal.

7. The optical switching element of claim 6, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

8. The optical switching element of claim 6, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a non-normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

9. The optical switching element of claim 6, wherein the first output signal comprises a majority of reflected portions of a first input signal received by the grating at a non-normal incident angle to the grating in the second position, and wherein the second output signal comprises a majority of reflected portions of a second input signal received by the grating at a non-normal incident angle to the grating in the second position.

10. The optical switching element of claim 1, wherein none of the strips has a width greater than 40 microns.

11. The optical switching element of claim 1, wherein the strips are operable to undergo a maximum rotation that is greater than 2 degrees.

12. The optical switching element of claim 1, wherein the circulator is operable to redirect the first output signal received from the variable blazed grating and to incur less than a three decibel loss in the redirected signal as compared to the output signal received by the circulator from the variable blazed grating.

13. The optical switching element of claim 1, wherein the circulator is operable to redirect the first output signal received from the variable blazed grating to prevent the first output signal from interfering with the input signal.

14. An optical switching element, comprising:

a variable blazed grating operable to receive a first optical input signal from a first input and to reflect the first signal toward a first output while the grating remains in a first position, the variable blazed grating further operable to undergo a displacement to a second position, the displacement resulting in a reflection of a majority of the first input signal toward a second output;

wherein the optical switching element is operable to switch between the first position and the second position and at a rate optimized for a packet size having at least a specified number of bytes being transmitted at a particular data rate.

15. The optical switching element of claim 14, wherein the rate is faster than once every microsecond.

16. The optical switching element of claim 14, wherein the rate is faster than once every 10 microseconds.

17. The optical switching element of claim 14, wherein the rate is faster than once every 30 microseconds.

18. The optical switching element of claim 14, wherein the packet size comprises an average packet size of packets encountered by the switching element.

19. The optical switching element of claim 14, wherein the packet size comprises between 40 and 60 bytes and wherein the rate comprises between once each 300 nanoseconds and once each 100 nanoseconds.

20. A method of processing optical signals using a variable blazed grafting the method comprising:

receiving at a variable blazed grating residing in a first position one or more optical input signals, the variable blazed grating comprising;

an inner conductive layer, and

a plurality of approximately adjacent at least partially reflective mirror strips disposed outwardly from the inner conductive layer, each strip operable to receive a portion of an input optical signal, wherein each of the plurality of strips is operable to undergo a partial rotation, the partial rotation resulting in a reflection of a majority of the input signal toward an output;

displacing the grating between a first position and a second position;

reflecting the input signals while the blazed grating remains at the first position;

for each input signal received, reflecting a majority of that input signal in a particular direction while the grating remains at the second position; and

receiving from the grating a first output signal at a first circulator disposed in the path of an input signal, the first circulator operable to redirect the first output signal from the path of the input signal.

21. The method of claim 20, wherein the first output signal comprises a reflected version of an input signal received by the grating at a normal incident angle to the grating in the first position.

22. The method of claim 20, wherein the first output signal comprises a reflected version of an input signal received by the grating at a non-normal incident angle to the grating in the first position.

23. The method of claim 20, wherein the first output signal comprises a majority of reflected portions of an input signal received by the grating at a normal incident angle to the grating in the second position.

24. The method of claim 20, wherein the first output signal comprises a majority of reflected portions of an input signal received by the grating at a non-normal incident angle to the grating in the second position.

25. The method of claim 20, further comprising receiving from the grating a second output signal at a second circulator disposed in the path of an input signal, the second circulator operable to redirect the second output signal from the path of the input signal.

26. The method of claim 25, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

27. The method of claim 25, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a non-normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

28. The method of claim 25, wherein the first output signal comprises a majority of reflected portions of a first input signal received by the grating at a non-normal incident angle to the grating in the second position, and wherein the second output signal comprises a majority of reflected portions of a second input signal received by the grating at a non-normal incident angle to the grating in the second position.

29. The method of claim 20, wherein none of the strips has a width greater than 40 microns.

30. The method of claim 20, wherein the strips are operable to undergo a maximum rotation that is greater than 2 degrees.

31. The method of claim 20, wherein the circulator is operable to redirect the first output signal received from the variable blazed grating and to incur less than a three decibel loss in the redirected signal as compared to the output signal received by the circulator from the variable blazed grating.

32. The method of claim 20, wherein the circulator is operable to redirect the first output signal received from the variable blazed grating to prevent the output signal interfering with the input signal.

33. An optical switching element comprising:

a variable blazed grating operable to receive and reflect one or more input signals while the grating remains in a first position and to receive and reflect one or more input signals while the grating remains in a second position;

a first circulator operable to receive from the variable blazed grating a first output signal traveling approximately along the path of an input signal to the grating but in an approximately opposite direction to that input signal, the circulator further operable to redirect the first output signal from the path of the input signal; and

a second circulator operable receive from the variable blazed grating a second output signal traveling approximately along the path of an input signal to the variable blazed grating but in an approximately opposite direction to that input signal, the circulator further operable to redirect the second output signal from the path of the input signal.

34. The optical switching element of claim 33, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

35. The optical switching element of claim 33, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a non-normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

36. The optical switching element of claim 33, wherein the first output signal comprises a majority of reflected portions of a first input signal received by the grating at a non-normal incident angle to the grating in the second position, and wherein the second output signal comprises a majority of reflected portions of a second input signal received by the grating at a non-normal incident angle to the grating in the second position.

37. The optical switching element of claim 33, wherein the first circulator is operable to redirect the first output signal received from the variable blazed grating and to incur less than a three decibel loss in the redirected signal as compared to the output signal received by the circulator from the variable blazed grating.

38. A method of processing optical signals using a variable blazed grating, the method comprising:

receiving at a variable blazed grating residing in a first position one or more optical input signals;

displacing the grating between a first position and a second position;

reflecting the input signals while the blazed grating remains at the first position;

for each input signal received, reflecting a majority of that input signal in a particular direction while the grating remains at the second position;

receiving from the grating a first output signal at a first circulator disposed in the path of an input signal, the first circulator operable to redirect the first output signal from the path of the input signal;

receiving from the grating a second output signal at a second circulator disposed in the path of an input signal, the second circulator operable to redirect the second output signal from the path of the input signal.

39. The method of claim 38, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

40. The method of claim 38, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a non-normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

41. The method of claim 38, wherein the first output signal comprises a majority of reflected portions of a first input signal received by the grating at a non-normal incident angle to the grating in the second position, and wherein the second output signal comprises a majority of reflected portions of a second input signal received by the grating at a non-normal incident angle to the grating in the second position.

42. The method of claim 38, wherein the first circulator is operable to redirect the first output signal received from the variable blared grating and to incur less than a three decibel loss in the redirected signal as compared to the output signal received by the circulator from the variable blazed grating.

43. An optical switching element comprising:

a variable blazed grating operable to receive and reflect one or more input signals while the grating remains in a first position and to receive and diffract one or more input signals while the grating remains in a second position, the variable blazed grating comprising;

an inner conductive layer; and

a plurality of approximately adjacent at least partially reflective mirror strips disposed outwardly from the inner conductive layer, each strip operable to receive a portion of an input optical signal wherein each of the plurality of strips is operable to undergo a partial rotation resulting in a reflection of a majority of the input signal toward an output; and

a first circulator operable to receive from the variable blazed grating a first output signal traveling approximately along the path of an input signal to the grating but in an approximately opposite direction to that input signal, the circulator further operable to redirect the first output signal from the path of the input signal.

44. The optical switching element of claim 43, wherein the first output signal comprises a reflected version of an input signal received by the grating at a normal incident angle to the grating in the first position.

45. The optical switching element of claim 43, wherein the first output signal comprises a reflected version of an input signal received by the grating at a non-normal incident angle to the grating in the first position.

46. The optical switching element of claim 43, wherein the first output signal comprises a majority of diffracted portions of an input signal received by the grating at a normal incident angle to the grating in the second position.

47. The optical switching element of claim 43, wherein the first output signal comprises a majority of diffracted portions of an input signal received by the grating at a non-normal incident angle to the grating in the second position.

48. The optical switching element of claim 43, further comprising a second circulator operable receive from the variable blazed grating a second output signal traveling approximately along the path of an input signal to the variable blazed grating but in an approximately opposite direction to that input signal, the circulator fixer operable to redirect the second output signal tom tie path of the input signal.

49. The optical switching element of claim 48, wherein the first output signal comprises a majority of diffracted portions of a first input signal received by the grating at a non-normal incident angle to the grating in the second position, and wherein the second output signal comprises a majority of diffracted portions of a second input signal received by the grating at a non-normal incident angle to the grating in the second position.

50. The optical switching element of claim 43, wherein the circulator is operable to redirect the first output signal received from the variable blazed grating and to incur less than a three decibel loss in the redirected signal as compared to the output signal received by the circulator from the variable blazed grating.

51. An optical switching element, comprising:

a variable blazed grating operable to receive a first optical input signal from a first input and to reflect the first signal toward a first output while the grating remains in a first position, the variable blazed grating further operable to undergo a displacement to a second position, the displacement resulting in a diffraction of a majority of the first input signal toward a second output;

wherein the the optical switching element is operable to switch between the first position and the second position and at a rate optimized for a packet size having at least a specified number of bytes being transmitted at a particular data rate.

52. The optical switching element of claim 51, wherein the rate is faster than once every 30 microseconds.

53. The optical switching element of claim 51, wherein the packet size comprises between 40 and 60 bytes and wherein the rate comprises between once each 300 nanoseconds and once each 100 nanoseconds.

54. A method of processing optical signals using a variable blazed grating, the method comprising:

receiving at a variable blazed grating residing in a first position one or more optical input signals, the variable blazed grating comprising;

an inner conductive layer; and

a plurality of approximately adjacent at least partially reflective mirror strips disposed outwardly from the inner conductive layer, each strip operable to receive a portion of an input optical signal, wherein each of the plurality of strips is operable to undergo a partial rotation, the partial rotation resulting in a reflection of a majority of the input signal toward an output;

displacing the grating between a first position and a second position;

reflecting the input signals while the blazed grating remains at the first position;

for each input signal received, diffracting a majority of that input signal in a particular direction while the grating remains at the second position; and

receiving from the grating a first output signal at a first circulator disposed in the path of an input signal, the first circulator operable to redirect the first output signal from the path of the input signal.

55. The method of claim 54, wherein the first output signal comprises a reflected version of an input signal received by the grating at a normal incident angle to the grating in the first position.

56. The method of claim 54, wherein the first output signal comprises a reflected version of an input signal received by the grating at a non-normal incident angle to the grating in the first position.

57. The method of claim 54, wherein the first output signal comprises a majority of diffracted portions of an input signal received by the grating at a normal incident angle to the grating in the second position.

58. The method of claim 54, wherein the first output signal comprises a majority of diffracted portions of an input signal received by the grating at a non-normal incident angle to the grating in the second position.

59. The method of claim 54, further comprising receiving from the grating a second output signal at a second circulator disposed in the path of an input signal, the second circulator operable to redirect the second output signal from the path of the input signal.

60. The method of claim 54, wherein the circulator is operable to redirect the first output signal received from the variable blazed grating and to incur less than a three decibel loss in the redirected signal as compared to the output signal received by the circulator from the variable blazed grating.

61. An optical switching element comprising:

a variable blazed grating operable to receive and reflect one or more input signals while the grating remains in a first position and to receive and diffract one or more input signals while the grating remains in a second position;

a first circulator operable to receive from the variable blazed grating a first output signal traveling approximately along the path of an input signal to the grating but in an approximately opposite direction to that input signal, the circulator further operable to redirect the first output signal from the path of the input signal; and

a second circulator operable receive from the variable blazed grating a second output signal traveling approximately along the path of an input signal to the variable blazed grating but in an approximately opposite direction to that input signal, the circulator further operable to redirect the second output signal from the path of the input signal.

62. The optical switching element of claim 61, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

63. The optical switching element of claim 61, wherein the first output signal comprises a reflected version of a first input signal received by the grating at a non-normal incident angle to the grating in the first position, and wherein the second output signal comprises a reflected version of a second input signal received by the grating at a non-normal incident angle to the grating in the first position.

64. The optical switching element of claim 61, wherein the first output signal comprises a majority of diffracted portions of a first input signal received by the grating at a non-normal incident angle to the grating in the second position, and wherein the second output signal comprises a majority of diffracted portions of a second input signal received by the grating at a non-normal incident angle to the grating in the second position.

65. The optical switching element of claim 61, wherein the first circulator is operable to redirect the first output signal received from the variable blazed grating and to incur less than three decibel loss in the redirected signal as compared to the output signal received by the circulator from the variable blazed grating.