Opto-electronic techniques for reducing phase noise in a carrier signal by carrier supression

• US 6,580,532 B1
• Filed: 01/28/2000
• Issued: 06/17/2003
• Est. Priority Date: 01/28/1999
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Maleki, Lute, Yao, Steve, Dick, John
• Primary Examiner(s): Pascal, Leslie
• Assistant Examiner(s): PAYNE, DAVID C
• Application Number:
  US09/493,642
• Time in Patent Office: 1,236 Days
• Field of Search: 359/111, 359/180, 359/183, 359/187, 359/127, 359/245, 372/29.011, 372/29.02, 372/29.03
• US Class Current: 398/39
• CPC Class Codes: H03L 7/04 wherein the frequency-determining element comprises distributed inductance and capacitance
• CPC Class Codes: H04B 10/2507 for the reduction or elimination of distortion or dispersion

Abstract

Systems and techniques for suppressing the carrier signal using an optical delay element and an electrical interferometer in an opto-electronic noise suppression module.

Claims

1. An opto-electronic device, comprising:

an oscillator to produce an oscillation signal at a carrier frequency, said oscillator responsive to a control signal to change a characteristic of said oscillation signal; and

a noise suppression module coupled to said oscillator to produce said control signal in response to said oscillation signal, said noise suppression module including;

an opto-electronic unit having an optical delay element and a photodetector to produce a first electrical signal indicative of said oscillation signal, and

an electrical interferometer coupled to said opto-electronic unit to interfere said first electrical signal with a second electrical signal indicative of said oscillation signal to produce a first output signal representing a destructive interference and a second output signal representing a constructive interference;

wherein said noise suppression module generates said control signal based on said first output signal from said electrical interferometer.

2. A device as in claim 1, wherein said oscillator produces an optical output that is modulated to carry said oscillation signal at said carrier frequency.

3. A device as in claim 2, wherein said noise suppression module includes an optical coupler to couple a portion of said optical output to said optical delay element.

4. A device as in claim 1, wherein said oscillation signal is an electrical signal, and said noise suppression module includes an electrical coupler to couple a portion of said oscillation signal to said opto-electronic unit, and

wherein said opto-electronic unit includes a laser transmitter to produce an optical output in response to said portion of said oscillation signal.

5. A device as in claim 4, wherein said laser transmitter includes a laser and an electro-optical modulator.

6. A device as in claim 1, wherein said noise suppression module includes a signal coupler that coupled a portion of said oscillation signal from said oscillator to produce said second electrical signal.

7. A device as in claim 6, wherein said signal coupler is an optical coupler.

8. A device as in claim 6, wherein said signal coupler is an electrical signal coupler.

9. A device as in claim 1, wherein said noise suppression module includes a phase shifting device coupled to control a phase difference between said first and second electrical signals.

10. A device as in claim 1, wherein said noise suppression module includes a device coupled to control a relative strength between said first and second electrical signals.

11. A device as in claim 1, wherein said electrical interferometer includes a RF coupler.

12. A device as in claim 1, wherein said noise suppression module includes a phase shifting device coupled to control a phase difference between said first and second output signals from said electrical interferometer.

13. A device as in claim 12, wherein said phase difference is Nπ

, where N is an integer.

14. A device as in claim 1, wherein said noise suppression module includes an electrical signal mixer coupled to receive at least said first output signal from said electrical interferometer.

15. A device as in claim 14, wherein said noise suppression module includes a signal amplifier coupled between said electrical interferometer and said signal mixer to amplify said first output signal.

16. A device as in claim 13, wherein said noise suppression module includes a low pass filter to control a bandwidth of said control signal.

17. A device as in claim 1, wherein said optical delay element includes a segment of optical fiber.

18. A device as in claim 1, wherein said optical delay element includes an optical resonator.

19. A device as in claim 18, wherein said optical resonator is a Fabry-Perot resonator.

20. A device as in claim 19, wherein said resonator encloses a segment of optical fiber.

21. A device as in claim 18, wherein said optical resonator is a ring resonator.

22. A device as in claim 21, wherein said optical resonator encloses a segment of optical fiber.

23. A device as in claim 18, wherein said optical resonator includes a resonator in whispering gallery modes.

24. A device as in claim 1, wherein said oscillator includes an optical signal path to support an optical wave which is modulated at said carrier frequency.

25. A device as in claim 24, wherein said optical signal path is coupled to said opto-electronic unit in said noise suppression module.

26. A device as in claim 25, wherein a portion of said optical signal path includes said optical delay element.

27. A device as in claim 23, wherein said optical path includes an optical medium of a type that produces a Brillouin scattering signal.

28. A device as in claim 1, further comprising a substrate on which said oscillator and said noise suppression are integrated.

29. A device as in claim 1, wherein said oscillator includes a dielectric resonator to produce an oscillation at a RF or microwave frequency.

30. A device as in claim 1, wherein said oscillator includes an acoustic resonator to produce an oscillation at a RF or microwave frequency.

31. A device as in claim 1, wherein said oscillator includes a microwave cavity.

32. A device as in claim 1, wherein said optical delay element includes an optical resonator to receive an optical signal indicative of said oscillation signal, wherein a center frequency of said optical signal is within a transmission peak of said optical resonator.

33. A device as in claim 1, wherein said carrier frequency is a multiple of a free spectral range of said optical resonator.

34. An opto-electronic device, comprising:

an optical modulator, having an electrical input port to accept an electrical modulation signal and an optical input port to receive an input optical signal at an optical frequency, to generate an output optical signal which is modulated to carry an oscillation signal at an oscillation frequency related to said electrical modulation signal; and

an opto-electronic unit, having an optical delay element coupled to receive at least a portion of said output optical signal and an electrical section coupled to said electrical input port to produce said electrical modulation signal, said electrical section including;

a photodetector to receive an optical transmission from said optical delay element to produce a first electrical signal;

an electrical interferometer coupled to receive said first electrical signal and a second electrical signal indicative of said oscillation signal to cause interference therebetween, to produce a first output signal representing a destructive interference and a second output signal representing a constructive interference;

a signal mixer coupled to receive and mix said first output signal from said electrical interferometer and a local oscillator electrical signal indicative of said oscillating signal to produce a first control signal; and

a phase shifting device coupled to control a phase of said second output signal from said electrical interferometer in response to said first control signal to produce said electrical modulation signal.

35. A device as in claim 34, wherein said electrical section includes an amplifier in a signal path between said phase shifting device and said interferometer.

36. A device as in claim 34, wherein said electrical section includes a band pass filter in a signal path between said phase shifting device and said interferometer.

37. A device as in claim 34, wherein said electrical section includes a low pass filter coupled in a signal path between said phase shifting device and said signal mixer to filter said first control signal.

38. A device as in claim 34, wherein said electrical section includes a phase shifting device coupled to control a phase difference between said first and second electrical signals.

39. A device as in claim 34, wherein said electrical section includes a device coupled to control a relative strength between said first and second electrical signals.

40. A device as in claim 34, wherein said electrical interferometer includes a RE coupler.

41. A device as in claim 34, wherein said electrical section includes a phase shifting device coupled to control a phase difference between said first and second output signals from said electrical interferometer.

42. A device as in claim 41, wherein said phase difference is Nπ

, where N is an integer.

43. A device as in claim 34, wherein said optical delay element includes a segment of optical fiber.

44. A device as in claim 34, wherein said optical delay element includes an optical resonator.

45. A device as in claim 44, wherein said optical resonator is a Fabry-Perot resonator.

46. A device as in claim 45, wherein said resonator encloses a segment of optical fiber.

47. A device as in claim 44, wherein said optical resonator is a ring resonator.

48. A device as in claim 47, wherein said optical resonator encloses a segment of optical fiber.

49. A device as in claim 44, wherein said optical resonator includes a resonator in whispering gallery modes.

50. A method for controlling an electrical controlled oscillator that produces an oscillation signal at a carrier frequency, comprising:

producing an optical signal that is modulated to carry the oscillation signal;

transmitting said optical signal through an optical delay element to produce a delayed optical transmission signal;

converting said optical transmission signal into a first electrical signal indicative of the oscillation signal,

producing a second electrical signal indicative of the oscillation signal;

interfering said first and said second electrical signals in an electrical interferometer to produce a first output signal representing a destructive interference and a second output signal representing a constructive interference; and

applying said second output signal to control the oscillator.

51. A method as in claim 50, further comprising controlling a phase difference between said first and second electrical signals.

52. A method as in claim 50, further comprising controlling a relative strength between said first and second electrical signals.

53. A method as in claim 50, further comprising controlling a phase difference between said first and second output signals from said electrical interferometer.

54. A method as in claim 53, wherein said phase difference is Nπ

, where N is an integer.

55. A method as in claim 53, further comprising using a signal mixer to mix said first and second output signals to produce an output that is substantially free of a contribution from said second output signal.

56. An opto-electronic device for controlling an oscillator which produces an oscillation signal at a carrier frequency, comprising:

an input port to receive an oscillation signal from an oscillator;

an opto-electronic unit having an optical delay element and a photodetector to produce a first electrical signal indicative of the oscillation signal;

an electrical interferometer coupled to said opto-electronic unit to interfere said first electrical signal with a second electrical signal indicative of the oscillation signal to produce a first output signal representing a destructive interference and a second output signal representing a constructive interference; and

an output port to generate a control signal to the oscillator based on said first output signal from said electrical interferometer.

57. A device as in claim 56, further including a phase shifting device coupled to control a phase difference between said first and second electrical signals.

58. A device as in claim 56, further including a device coupled to control a relative strength between said first and second electrical signals.

59. A device as in claim 56, further including a phase shifting device coupled to control a phase difference between said first and second output signals from said electrical interferometer.

60. A device as in claim 59, wherein said phase difference is Nπ

, where N is an integer.

61. A device as in claim 56, further including a signal mixer coupled to receive said first output signal from said electrical interferometer and another electrical signal indicative of the oscillation signal to produce said control signal at said output port.

62. An opto-electronic device, comprising:

an optical coupler having first and second input ports to receive input beams from two different lasers and first and second output ports;

an optical delay element coupled to said first output port of said optical coupler;

a first photodetector coupled to receive an output from said optical delay element to produce a first electrical signal;

a second photodetector coupled to receive an output from said second output port of said optical coupler to produce a second electrical signal;

an electrical interferometer having a first input to receive said first electrical signal and a second input to receive said second electrical signal, said electrical interferometer causing interference between said first and said second electrical signals to produce a first output signal representing a destructive interference and a second output signal representing a constructive interference;

a signal mixer to mix said first and second output signals to produce a control signal based on said first output signal; and

an output port to output said control signal.

63. A device as in claim 62, further including a phase shifting device coupled to control a phase difference between said first and second output signals from said electrical interferometer.

64. A device as in claim 63, wherein said phase difference is Nπ

, where N is an integer.