Dispersion compensating nonlinear polarization amplifiers

• US 6,693,737 B2
• Filed: 03/05/2001
• Issued: 02/17/2004
• Est. Priority Date: 03/24/1998
• Status: Expired due to Term

• Current Assignee: Neptune Subsea IP Ltd. (Xtera Topco Ltd.)
• Original Assignee: Xtera Communications Incorporated (Xtera Topco Ltd.)
• Inventors: Islam, Mohammed N.
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US09/800,085
• Publication Number:
  US 20020067537A1
• Time in Patent Office: 1,079 Days
• Field of Search: 359/334, 359/337.5, 359/341.31, 359/341.5, 372/3, 372/6
• US Class Current: 359/334
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/094011 with bidirectional pumping, i.e. with injection of the pump light from both two ends of the fibre
• CPC Class Codes: H01S 3/094015 with pump light recycling, i.e. with reinjection of the unused pump light back into the fiber, e.g. by reflectors or circulators
• CPC Class Codes: H01S 3/094096 Multi-wavelength pumping
• CPC Class Codes: H01S 3/1083 using parametric generation
• CPC Class Codes: H01S 3/302 in an optical fibre
• CPC Class Codes: H01S 5/50 Amplifier structures not provided for in groups H01S5/02 - H01S5/30
• CPC Class Codes: H04B 10/291 in which processing or amplification is carried out without conversion of the main signal from optical form
• CPC Class Codes: H04B 10/2916 using Raman or Brillouin amplifiers
• CPC Class Codes: H04B 2210/003 Devices including multiple stages, e.g., multi-stage optical amplifiers or dispersion compensators
• CPC Class Codes: H04B 2210/258 treating each wavelength or wavelength band separately

Abstract

A broadband nonlinear polarization amplifier includes an input port for inputting an optical signal having a wavelength λ. A distributed gain medium receives and amplifiers the optical signal through nonlinear polarization. The distributed gain medium has zero-dispersion at wavelength λ₀. A magnitude of dispersion at λ is less than 50 ps/nm-km. One or more semiconductor lasers are operated at wavelengths λ_p for generating a pump light to pump the distributed gain medium. An output port outputs the amplified optical signal.

Claims

1. A broadband fiber transmission system, comprising:

a transmission line comprising at least one zero dispersion wavelength λ

_o and transmitting an optical signal comprising a wavelength λ

, the transmission line comprising a Raman amplifier that amplifies the optical signal through Raman gain, at least a portion of the transmission line comprises a magnitude of dispersion at the wavelength λ

between 10 ps/nm-km and 50 ps/nm-kin; and

one or more semiconductor lasers operated at wavelengths λ

_p for generating a pump light to pump the Raman amplifier, wherein the wavelength λ

is within thirty (30) nanometers of the at least one zero dispersion wavelength λ

₀ and wherein the at least one zero dispersion wavelength λ

₀ is less than 1540 nm or greater than 1560 nm.

2. The broadband fiber transmission system of claim 1, wherein a sign of dispersion at the wavelength λ

is negative.

3. The broadband fiber transmission system of claim 1, wherein the Raman amplifier comprises a distributed Raman amplifier.

4. The broadband fiber transmission system of claim 1, wherein the magnitude of dispersion at the wavelength λ

is less than 40 ps/nm-km.

5. The broadband fiber transmission system of claim 1, wherein the magnitude of dispersion at the wavelength λ

is less than 30 ps/nm-km.

6. The broadband fiber transmission system of claim 1, wherein the magnitude of dispersion at the wavelength λ

is less than 20 ps/nm-km.

7. The broadband fiber transmission system of claim 1, wherein the wavelength λ

is within 20 nm of the at least one zero dispersion wavelength λ

₀.

8. The broadband fiber transmission system of claim 1, wherein the optical signal comprises a wavelength λ

in the range of 1400 nm to 1530 nm.

9. The broadband fiber transmission system of claim 1, wherein the optical signal comprises a wavelength X in the range of 1530 nm to 1650 nm.

10. The broadband fiber transmission system of claim 1, wherein a signal wavelength at λ

is sufficiently low in power to avoid at least one fiber non-linearity effect.

11. The broadband fiber transmission system of claim 1, wherein the Raman amplifier comprises sufficient gain to compensate for losses in the transmission line.

12. The broadband fiber transmission system of claim 10, wherein the at least one fiber non-linearity effect comprises four-wave mixing.

13. The broadband fiber transmission system of claim 10, wherein the at least one fiber non-linearity effect comprises modulation instability.

14. A broadband fiber transmission system, comprising:

a transmission line comprising at least one zero dispersion wavelength λ

_o and transmitting an optical signal comprising a wavelength λ

, the transmission line comprising a serial combination of a Raman amplifier and a discrete optical amplifier that amplify the optical signal, at least a portion of the transmission line comprises a magnitude of dispersion at the wavelength λ

less than 50 ps/nm-kin; and

one or more semiconductor lasers operated at wavelengths λ

_p for generating a pump light to pump the amplifiers, wherein the wavelength λ

is within thirty (30) nanometers of the at least one zero dispersion wavelength λ

₀ and wherein the at least one zero dispersion wavelength λ

₀ is less than 1540 nm or greater than 1560 nm.

15. The broadband fiber transmission system of claim 14, wherein a sign of dispersion at the wavelength λ

is negative.

16. The broadband fiber transmission system of claim 14, wherein the Raman amplifier comprises a distributed Raman amplifier.

17. The broadband fiber transmission system of claim 14, wherein the magnitude of dispersion at the wavelength λ

is less than 40 ps/nm-km.

18. The broadband fiber transmission system of claim 14, wherein the magnitude of dispersion at the wavelength λ

is less than 30 ps/nm-km.

19. The broadband fiber transmission system of claim 14, wherein the magnitude of dispersion at the wavelength λ

is less than 20 ps/nm-km.

20. The broadband fiber transmission system of claim 14, wherein the wavelength λ

is within 20 nm of the at least one zero dispersion wavelength λ

₀.

21. The broadband fiber transmission system of claim 14, wherein the optical signal comprises the wavelength λ

in the range of 1400 nm to 1530 nm.

22. The broadband fiber transmission system of claim 14 wherein the optical signal comprises the wavelength λ

in the range of 1530 nm to 1650 nm.

23. The broadband fiber transmission system of claim 14, wherein the discrete optical amplifier comprises a rare earth doped amplifier.

24. The broadband fiber transmission system of claim 14, wherein the discrete optical amplifier comprises an erbium doped fiber amplifier.

25. The broadband fiber transmission system of claim 14, wherein the discrete optical amplifier comprises a Raman amplifier.

26. The broadband fiber transmission system of claim 14, wherein the discrete optical amplifier comprises a thulium doped fiber amplifier.

27. The broadband fiber transmission system of claim 14, wherein a signal wavelength at λ

is sufficiently low in power to avoid at least one fiber non-linearity effect.

28. The broadband fiber transmission system of claim 14, wherein the amplifiers comprise sufficient gain to compensate for losses in the transmission line.

29. The broadband fiber transmission system of claim 27, wherein the at least one fiber non-linearity effect comprises four-wave mixing.

30. The broadband fiber transmission system of claim 27, wherein the at least one fiber non-linearity effect comprises modulation instability.

31. A method for transmitting an optical signal over a broadband transmission system, comprising:

transmitting an optical signal comprising a wavelength λ

through a transmission line comprising at least one zero dispersion wavelength λ

₀, the transmission line comprising a Raman amplifier that amplifies the optical signal through Raman gain, at least a portion of the transmission line comprises a magnitude of dispersion at the wavelength λ

between 10 ps/nm-km and 50 ps/nm-kin; and

introducing to the Raman amplifier a pump light to pump, wherein the wavelength λ

is within thirty (30) nanometers of the at least one zero dispersion wavelength λ

₀ and wherein the at least one zero dispersion wavelength λ

₀ is less than 1540 nm or greater than 1560 nm.

32. The method of claim 31, wherein the pump light to pump the Raman amplifier is generated by one or more semiconductor lasers operated at wavelengths λ

_p.

33. The method of claim 31, wherein the Raman amplifier comprises a distributed Raman amplifier.

34. The method of claim 31, wherein wherein the magnitude of dispersion at the wavelength λ

is less than 40 ps/nm-km.

35. The method of claim 31, wherein the magnitude of dispersion at the wavelength λ

is less than 30 ps/nm-km.

36. The method of claims 31, wherein the magnitude of dispersion at the wavelength λ

is less than 20 ps/nm-km.

37. The method of claim 31, the wavelength λ

is within 20 nm of the at least one zero dispersion wavelength λ

₀.

38. The method of claim 31, wherein the optical signal comprises a wavelength λ

in the range of 1400 nm to 1530 nm.

39. The method of claim 31, wherein the optical signal comprises a wavelength λ

is in the range of 1530 nm to 1650 nm.

40. The method of claim 31, wherein a signal wavelength at λ

is sufficiently low in power to avoid at least one fiber non-linearity effect.

41. The method of claim 31, wherein the Raman amplifier comprises sufficient gain to compensate for losses in the transmission line.

42. A method for transmitting an optical signal over a broadband transmission system, comprising:

transmitting an optical signal comprising a wavelength λ

through a transmission line comprising at least one zero dispersion wavelength λ

₀, the transmission line comprising a serial combination of a Raman amplifier and a discrete optical amplifier that amplify the optical signal, at least a portion of the transmission line comprises a magnitude of dispersion at the wavelength λ

less than 50 ps/nm-kin; and

introducing to the transmission line a pump light to pump at least one of the amplifiers, wherein the wavelength λ

is within thirty (30) nanometers of the at least one zero dispersion wavelength λ

₀ and wherein the at least one zero dispersion wavelength λ

₀ is less than 1540 nm or greater than 1560 nm.

43. The method of claim 42, wherein the pump light to pump the Raman amplifier is generated by one or more semiconductor lasers operated at wavelengths λ

_p.

44. The method of claim 42, wherein the Raman amplifier comprises a distributed Raman amplifier.

45. The method of claim 42, wherein wherein the magnitude of dispersion at the wavelength λ

is less than 40 ps/nm-km.

46. The method of claim 42, wherein the magnitude of dispersion at the wavelength λ

is less than 30 ps/nm-km.

47. The method of claim 42, wherein the magnitude of dispersion at the wavelength λ

is less than 20 ps/nm-km.

48. The method of claim 42, wherein the wavelength λ

is within 20 nm of the at least one zero dispersion wavelength λ

₀.

49. The method of claim 42, wherein the optical signal comprises a wavelength λ

in the range of 1400 nm to 1530 nm.

50. The method of claim 42, wherein the optical signal comprised a wavelength λ

is in the range of 1530 nm to 1650 nm.

51. The method of claim 42, wherein a signal wavelength at λ

is sufficiently low in power to avoid at least one fiber non-linearity effect.

52. The method of claim 42, wherein the Raman amplifier comprises sufficient gain to compensate for losses in the transmission line.