Nonlinear polarization amplifiers in nonzero dispersion shifted fiber

• US 6,919,986 B2
• Filed: 07/25/2003
• Issued: 07/19/2005
• Est. Priority Date: 05/05/2000
• 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): Tarcza, Thomas H.
• Assistant Examiner(s): Hughes, Deandra M.
• Application Number:
  US10/627,572
• Publication Number:
  US 20040130777A1
• Time in Patent Office: 725 Days
• Field of Search: 359/334
• US Class Current: 359/334
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/083 Ring lasers fibre ring lasers H01S3/06791
• 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: 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 fiber transmission system includes a transmission line with at least one zero dispersion wavelength λ_o and transmits an optical signal of λ. The transmission line includes a distributed Raman amplifier that amplifies the optical signal through Raman gain. One or more pump sources are included and operated at wavelengths λ_p for generating a pump light to pump the Raman amplifier. λ is close to λ₀ and λ₀ is less than 1540 nm or greater than 1560 nm.

Claims

1. A broadband fiber transmission system, comprising:

a transmission line having at least a first zero dispersion wavelength λ

₀₁ and a second zero dispersion wavelength λ

₀₂, the transmission line operable to transmit an optical signal comprising a wavelength λ

, the transmission line including a Raman gain medium that amplifies the optical signal through Raman gain; and

one or more pump sources operated at wavelengths λ

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

₀₁ is separated from λ

₀₂ by at least 50 nm.

2. The broadband fiber transmission system of claim 1, wherein λ

is within 30 nm of at least one of λ

₀₁ and λ

₀₂.

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

in the range of 1430 nm and 1630 nm.

4. The broadband fiber transmission system of claim 1, wherein the transmission line comprises at least a first optical fiber and a second optical fiber coupled to the first optical fiber.

5. The broadband fiber transmission system of claim 1, wherein the transmission line comprises at least a first portion having a positive sign of dispersion and a second portion having a negative sign of dispersion.

6. The broadband fiber transmission system of claim 1, wherein the Raman gain medium comprises a distributed Raman gain medium.

7. The broadband fiber transmission system of claim 1, wherein the Raman gain medium comprises a discrete Raman gain medium.

8. The broadband fiber transmission system of claim 1, wherein the pump light generated by the at least one pump source propagates in the Raman gain medium in a direction that is substantially opposite the direction that the optical signal propagates the Raman gain medium.

9. The broadband fiber transmission system of claim 1, wherein λ

comprises one of a plurality of signal wavelengths forming the optical signal.

10. The broadband fiber transmission system of claim 1, wherein at least one of the one or more pump sources comprises a semiconductor laser.

11. A method of broadband amplification, comprising:

transmitting an optical signal comprising a wavelength λ

within a broadband fiber transmission system comprising a transmission line having at least a first zero dispersion wavelength λ

₀₁ and a second zero dispersion wavelength λ

₀₂, the transmission line including a Raman gain medium that amplifies an optical signal through Raman gain; and

pumping the Raman amplifier with pump light λ

_p, wherein λ

₀₁ is separated from λ

₀₂ by at least 50 nm.

12. The method of claim 11, wherein λ

is within 30 nm of at least one of λ

₀₁ and λ

₀₂.

13. The method of claim 11, wherein the optical signal has a wavelength λ

in the range of 1430 nm and 1630 nm.

14. The method of claim 11, wherein the Raman gain medium is a distributed Raman gain medium or a discrete Raman gain medium.

15. The method of claim 11, wherein the transmission line comprises at least a first optical fiber and a second optical fiber coupled to the first optical fiber.

16. The method of claim 11, wherein the transmission line comprises at least a first portion having a positive sign of dispersion and a second portion having a negative sign of dispersion.

17. The method of claim 11, wherein the pump light propagates in the Raman gain medium in a direction that is substantially opposite the direction that the optical signal propagates the Raman gain medium.

18. The method of claim 11, wherein λ

comprises one of a plurality of signal wavelengths forming the optical signal.

19. The method of claim 11, wherein at least one of the one or more pump sources comprises a semiconductor laser.

20. A broadband fiber transmission system, comprising:

a transmission line having at least a first zero dispersion wavelength λ

₀₁ and a second zero dispersion wavelength λ

₀₂, the transmission line operable to transmit an optical signal comprising a wavelength λ

, the transmission line including a Raman gain medium that amplifies the optical signal through Raman gain; and

one or more pump sources operated at wavelengths λ

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

is within 30 nm of at least one of λ

₀₁ and λ

₀₂.

21. The broadband fiber transmission system of claim 20, wherein λ

₀₁ is separated from λ

₀₂ by at least 50 nm.

22. The broadband fiber transmission system of claim 20, wherein the Raman gain medium is a distributed Raman gain medium or a discrete Raman gain medium.

23. The broadband fiber transmission system of claim 20, wherein the pump light generated by the at least one pump source propagates in the Raman gain medium in a direction that is substantially opposite the direction that the optical signal propagates the Raman gain medium.

24. The broadband fiber transmission system of claim 20, wherein λ

comprises one of a plurality of signal wavelengths forming the optical signal.

25. The broadband fiber transmission system of claim 24, wherein at least some of the plurality of signal wavelengths have a wavelength in the range of 1430 nm and 1630 nm.

26. A method of broadband amplification, comprising:

transmitting an optical signal comprising a wavelength λ

within a broadband fiber transmission system comprising a transmission line having at least a first zero dispersion wavelength λ

₀₁ and a second zero dispersion wavelength λ

₀₂, the transmission line including a Raman gain medium that amplifies an optical signal through Raman gain; and

pumping the Raman amplifier with pump light λ

_p, wherein λ

is within 30 nm of at least one of λ

₀₁ and λ

₀₂.

27. The method of claim 26, wherein the Raman gain medium is a distributed Raman gain medium or a discrete Raman gain medium.

28. The method of claim 26, wherein the pump light propagates in the Raman gain medium in a direction that is substantially opposite the direction that the optical signal propagates the Raman gain medium.

29. The method of claim 26, wherein λ

comprises one of a plurality of signal wavelengths forming the optical signal.

30. The method of claim 29, wherein at least some of the plurality of signal wavelengths have a wavelength in the range of 1430 nm and 1630 nm.