Wide-band raman amplifiers

1. An optical fiber amplifier comprising:

an optical fiber having a zero-dispersion wavelength; and

at least one Raman pump that provides pump power to said optical fiber at a predetermined wavelength, wherein said predetermined wavelength is near said zero-dispersion wavelength;

wherein said pump power from said at least one Raman pump is provided at said predetermined wavelength to allow transfer of at least a portion of said pump power to a first adjacent wavelength that is less than said zero-dispersion wavelength, and to a second adjacent wavelength that is greater than said zero-dispersion wavelength.

2. The optical fiber amplifier of claim 1 , wherein said predetermined wavelength is within about 5 nm inclusive from said zero-dispersion wavelength of said optical fiber.

3. The optical fiber amplifier of claim 2 , wherein said predetermined wavelength is within about 1 nm inclusive from said zero-dispersion wavelength of said optical fiber.

4. The optical fiber amplifier of claim 1 , wherein said predetermined wavelength is substantially same as said zero-dispersion wavelength of said optical fiber.

5. The optical fiber amplifier of claim 1 , further comprising a short-wavelength Raman pump that provides pump power to said optical fiber at said first adjacent wavelength, said pump power from said short-wavelength Raman pump being augmented by said portion of said pump power from said at least one Raman pump that is transferred to said first adjacent wavelength.

6. The optical fiber amplifier of claim 1 , further comprising a long-wavelength Raman pump that provides pump power to said optical fiber at said second adjacent wavelength, said pump power from said long-wavelength Raman pump being augmented by said portion of said pump power from said at least one Raman pump that is transferred to said second adjacent wavelength.

7. The optical fiber amplifier of claim 1 , wherein said first adjacent wavelength and said second adjacent wavelength are substantially symmetrically positioned about said zero-dispersion wavelength.

8. The optical fiber amplifier of claim 1 , wherein midpoint between said first adjacent wavelength and said second adjacent wavelength is within about 5 nm inclusive from said zero-dispersion wavelength.

9. The optical fiber amplifier of claim 8 , wherein midpoint between said first adjacent wavelength and said second adjacent wavelength is within about 1 nm from said zero-dispersion wavelength.

10. The optical fiber amplifier of claim 1 , wherein said at least one Raman pump is a first Raman pump that provides pump power to said optical fiber at a wavelength less than said zero-dispersion wavelength, and a second Raman pump that provides pump power to said optical fiber at a wavelength greater than said zero-dispersion wavelength.

11. The optical fiber amplifier of claim 10 , wherein said zero-dispersion wavelength is substantially midway between wavelength of said first Raman pump and wavelength of said second Raman pump.

12. The optical fiber amplifier of claim 10 , wherein midpoint between wavelength of said first Raman pump and wavelength of said second Raman pump is within 5 nm inclusive from said zero-dispersion wavelength.

13. The optical fiber amplifier of claim 12 , wherein midpoint between wavelength of said first Raman pump and wavelength of said second Raman pump is within 1 nm inclusive from said zero-dispersion wavelength.

14. The optical fiber amplifier of claim 1 , wherein said zero-dispersion wavelength of said optical fiber is in a range between approximately 1400 nm to 1520 nm inclusive.

15. The optical fiber amplifier of claim 14 , wherein said zero-dispersion wavelength of said optical fiber is in a range between approximately 1445 nm to 1455 nm inclusive.

16. The optical fiber amplifier of claim 14 , wherein said zero-dispersion wavelength of said optical fiber is in a range between approximately 1490 mm to l1550 nm inclusive.

17. A method of improving performance of a wide-band Raman amplifier comprising the step of:

providing an optical fiber having a zero-dispersion wavelength; and

providing Raman pump power to said optical fiber at a predetermined wavelength in a manner that at least a portion of said pump power is transferred to a first adjacent wavelength that is less than said zero-dispersion wavelength, and at least a portion of said pump power is transferred to a second adjacent wavelength that is greater than said zero-dispersion wavelength, wherein said predetermined wavelength is near said zero-dispersion wavelength.

18. The method of claim 17 , wherein said predetermined wavelength is within about 5 nm inclusive from said zero-dispersion wavelength of said optical fiber.

19. The method of claim 18 , wherein said predetermined wavelength is within about 1 nm inclusive from said zero-dispersion wavelength of said optical fiber.

20. The method of claim 17 , wherein said predetermined wavelength is substantially same as said zero-dispersion wavelength of said optical fiber.

21. The method of claim 17 , further including the step of providing a short-wavelength Raman pump power to said optical fiber at said first adjacent wavelength, said short-wavelength Raman pump power being augmented by said portion of said Raman pump power that is transferred to said first adjacent wavelength.

22. The method of claim 17 , further including the step of providing a long-wavelength Raman pump power to said optical fiber at said second adjacent wavelength, said long-wavelength Raman pump power being augmented by said portion of said Raman pump power that is transferred to said second adjacent wavelength.

23. The method of claim 17 , wherein said first adjacent wavelength and said second adjacent wavelength are substantially symmetrically positioned about said zero-dispersion wavelength.

24. The method of claim 17 , wherein midpoint between said first adjacent wavelength and said second adjacent wavelength is within about 5 nm inclusive from said zero-dispersion wavelength.

25. The method of claim 24 , wherein midpoint between said first adjacent wavelength and said second adjacent wavelength is within about 1 nm inclusive from said zero-dispersion wavelength.

26. The method of claim 17 , wherein said step of providing Raman pump power includes the step of providing pump power at a wavelength less than said zero-dispersion wavelength, and providing pump power at a wavelength greater than said zero-dispersion wave length.

27. The method of claim 26 , wherein said zero-dispersion wavelength is substantially midway between said wavelength less than said zero-dispersion wavelength and said wavelength greater than said zero-dispersion wavelength.

28. The method of claim 26 , wherein midpoint between said wavelength less than said zero-dispersion wavelength and said wavelength greater than said zero-dispersion wavelength is within about 5 nm inclusive from said zero-dispersion wavelength.

29. The method of claim 28 , wherein midpoint between said wavelength less than said zero-dispersion wavelength and said wavelength greater than said zero-dispersion wavelength is within about 1 nm inclusive from said zero-dispersion wavelength.

30. The method of claim 17 , wherein said zero-dispersion wavelength of said optical fiber is in a range between approximately 1400 nm to 1520 nm inclusive.

31. The method of claim 30 , wherein said zero-dispersion wavelength of said optical fiber is in a range between approximately 1445 nm to 1455 nm inclusive.

32. The method of claim 30 , wherein said zero-dispersion wavelength of said optical fiber is in a range between approximately 1490 nm to 1550 nm inclusive.