Dynamic alignment of optical fibers to optical circuit devices such as planar lightwave circuits

1. A method of aligning an optical fiber array relative to an optical circuit device, the optical fiber array being coupled to the optical circuit device, the method comprising:

coupling an optical signal source to one end of the optical fiber array, the other end of the optical fiber array being coupled to a side of the optical circuit device, the optical signal source adapted to transmit an optical signal to the optical fiber array;

coupling an optical measuring device to the one end of the optical fiber array, the other end of the optical fiber array being coupled to the same side of the optical circuit device, the optical measuring device adapted to measure a characteristic of an optical signal received from the optical fiber array;

establishing an initial optical path from the optical signal source to the optical fiber array to the optical circuit device to the optical fiber array and to the optical measuring device;

measuring the characteristic of an optical signal received by the optical measuring device from the optical fiber array; and

moving the relative position of the optical fiber array and the optical circuit device to change the optical path until the measured characteristic indicates that the alignment of the optical path is satisfactory.

2. The method of claim 1 wherein the optical path from the optical signal source to the optical measuring device is “U”-shaped.

3. The method of claim 1 wherein the moving step changes the optical path until the measured characteristic indicates that the alignment of the optical path is optimal.

4. The method of claim 1 wherein the moving step changes the optical path until the measured characteristic indicates that the alignment of the optical path is above a threshold.

5. The method of claim 1 further comprising fixing the relative positions of the optical fiber array and the optical circuit device.

6. The method of claim 5 wherein the fixing step bonds or adheres the optical fiber array to the optical circuit device.

7. The method of claim 1 wherein the optical fiber array is a single optical fiber.

8. The method of claim 1 wherein the optical fiber array includes an optical waveguide.

9. The method of claim 1 wherein the optical signal source and the optical measuring device are coupled to different optical fibers of the optical fiber array.

10. The method of claim 1 further comprising using a mechanical reference to assist establishing the initial optical path.

11. The method of claim 1 wherein the mechanical reference is a mark made on the optical fiber array and the optical circuit device.

12. The method of claim 1 wherein the moving step moves the relative position of the optical fiber array and the optical circuit device in a random manner.

13. The method of claim 1 wherein the moving step moves the relative position of the optical fiber array and the optical circuit device in a systematic manner.

14. The method of claim 1 wherein the moving step rotates the relative position of the optical fiber array and the optical circuit device.

15. The method of claim 1 wherein the moving step translates the relative position of the optical fiber array and the optical circuit device.

16. The method of claim 1 wherein the moving step rotates and translates the relative position of the optical fiber array and the optical circuit device.

17. The method of claim 1 wherein the characteristic is the intensity of the optical signal.

18. The method of claim 17 wherein the moving step changes the optical path until the intensity of the optical signal is a maximum.

19. The method of claim 17 wherein the moving step changes the optical path until the intensity of the optical signal exceeds a threshold.

20. The method of claim 1 wherein the characteristic is the insertion loss of the optical signal.

21. The method of claim 20 wherein the moving step changes the optical path until the insertion loss of the optical signal is a minimum.

22. The method of claim 20 wherein the moving step changes the optical path until the intensity of the optical signal is below a threshold.

23. The method of claim 1 wherein the optical circuit device comprises a planar lightwave circuit.

24. The method of claim 23 wherein the optical path from the optical signal source to the planar lightwave circuit is “U”-shaped.

25. The method of claim 23 wherein the moving step changes the optical path until the measured characteristic indicates that the alignment of the optical path is optimal.

26. The method of claim 23 wherein the moving step changes the optical path until the measured characteristic indicates that the alignment of the optical path is above a threshold.

27. The method of claim 23 wherein the moving step rotates the relative position of the optical fiber array and the optical circuit device.

28. The method of claim 23 wherein the moving step translates the relative position of the optical fiber array and the optical circuit device.

29. The method of claim 23 wherein the moving step rotates and translates the relative position of the optical fiber array and the optical circuit device.

30. The method of claim 23 wherein the characteristic is the intensity of the optical signal.

31. The method of claim 30 wherein the moving step changes the optical path until the intensity of the optical signal is a maximum.

32. The method of claim 30 wherein the moving step changes the optical path until the intensity of the optical signal exceeds a threshold.

33. The method of claim 23 wherein the characteristic is the insertion loss of the optical signal.

34. The method of claim 33 wherein the moving step changes the optical path until the insertion loss of the optical signal is a minimum.

35. The method of claim 33 wherein the moving step changes the optical path until the intensity of the optical signal is below a threshold.

36. The method of claim 23 further comprising fixing the relative positions of the optical fiber array and the planar lightwave circuit.

37. The method of claim 36 wherein the fixing step bonds or adheres the optical fiber array to the planar lightwave circuit.

38. A system adapted to align a first and second light-guiding element, the system comprising:

an optical signal source coupled to transmit an optical signal to the first light-guiding element, the first light-guiding element being coupled to and adapted to propagate the transmitted optical signal to an input of the second light-guiding element, the second light-guiding element being adapted to propagate the transmitted optical signal from its output to the first light-guiding element, the input and output of the second light-guiding element being located on the same side of the second light-guiding element;

an optical measuring device coupled to receive the transmitted optical signal from the first light-guiding element, the first light-guiding element comprising an optical fiber array, thereby forming an optical path from the optical signal source to the first light-guiding element to the input of the second light-guiding element to the output of the second light-guiding element to the first light-guiding element and to the optical measuring device, the optical measuring device being adapted to measure a characteristic of the received optical signal;

a control circuit coupled to the optical measuring device and to a movable structure, the movable structure being coupled to move the relative position of the first and second light-guiding elements, the control circuit processes information from optical measuring device, determines whether the characteristic of the received optical signal is satisfactory, and controls whether the movable structure moves the relative position of the first and second light-guiding elements to change the optical path;

wherein the relative positions of the first and second light-guiding elements may be changed to alter the optical path until the optical measuring device determines that the characteristic of the received optical signal is satisfactory.

39. The system of claim 38 wherein the optical fiber array is a single optical fiber.

40. The system of claim 38 wherein the movable structure moves the relative position of the first and second light-guiding elements in a random manner.

41. The system of claim 38 wherein the movable structure rotates the relative position of the first and second light-guiding elements.

42. The system of claim 38 wherein the movable structure translates the relative position of the first and second light-guiding elements.

43. The system of claim 38 wherein the movable structure rotates and translates the relative position of the first and second light-guiding elements.

44. The system of claim 38 wherein the optical path from the optical signal source to the optical measuring device is “U”-shaped.

45. The system of claim 38 wherein the changes the optical path until the measured characteristic indicates that the alignment of the optical path is optimal.

46. The system of claim 38 wherein the changes the optical path until the measured characteristic indicates that the alignment of the optical path is above a threshold.

47. The system of claim 38 wherein the characteristic is the intensity of the optical signal.

48. The system of claim 47 wherein the changes the optical path until the intensity of the optical signal is a maximum.

49. The system of claim 47 wherein the changes the optical path until the intensity of the optical signal exceeds a threshold.

50. The system of claim 38 wherein the characteristic is the insertion loss of the optical signal.

51. The system of claim 38 wherein the control circuit changes the optical path until the insertion loss of the optical signal is a minimum.

52. The system of claim 51 wherein the control circuit changes the optical path until the intensity of the optical signal is below a threshold.

53. The system of claim 38 wherein the comprises a planar lightwave circuit.

54. The system of claim 38 wherein the optical signal source and the optical measuring device are disposed on an optical device chip.

55. A system adapted to align a first and second light-guiding element, the system comprising:

an optical signal source coupled to transmit an optical signal to the first light-guiding element, the first light-guiding element being coupled to and adapted to propagate the transmitted optical signal to an input of the second light-guiding element, the second light-guiding element comprising an optical circuit device, the optical circuit device including a planar lightwave circuit, the second light-guiding element being adapted to propagate the transmitted optical signal from its output to the first light-guiding element, the input and output of the second light-guiding element being located on the same side of the second light-guiding element;

an optical measuring device coupled to receive the transmitted optical signal from the first light-guiding element, thereby forming an optical path from the optical signal source to the first light-guiding element to the input of the second light-guiding element to the output of the second light-guiding element to the first light-guiding element and to the optical measuring device, the optical measuring device being adapted to measure a characteristic of the received optical signal;

a control circuit coupled to the optical measuring device and to a movable structure, the movable structure being coupled to move the relative position of the first and second light-guiding elements, the control circuit processes information from optical measuring device, determines whether the characteristic of the received optical signal is satisfactory, and controls whether the movable structure moves the relative position of the first and second light-guiding elements to change the optical path;

wherein the relative positions of the first and second light-guiding elements may be changed to alter the optical path until the optical measuring device determines that the characteristic of the received optical signal is satisfactory.

56. The system of claim 55 wherein the movable structure moves the relative position of the first and second light-guiding elements in a random manner.

57. The system of claim 55 wherein the first light-guiding element includes an optical fiber array.

58. The system of claim 55 further comprising a single optical fiber coupled to the first light-guiding element.

59. The system of claim 55 wherein the optical signal source and the optical measuring device are disposed on an optical device chip.