System and Method for Mitigating Four-Wave-Mixing Effects

• US 20140050480A1
• Filed: 10/28/2013
• Published: 02/20/2014
• Est. Priority Date: 04/13/2011
• Status: Active Grant

• Current Assignee: Fred S. Hirt, Kuang-Yi Wu, Mary R. Phillips
• Original Assignee: Fred S. Hirt, Kuang-Yi Wu, Mary R. Phillips
• Inventors: Wu, Kuang-Yi, Phillips, Mary R., Hirt, Fred S.
• Granted Patent: US 9,479,261 B2
• Time in Patent Office: Days
• US Class Current: 398/79
• CPC Class Codes: H04B 10/2563 Four-wave mixing [FWM]
• CPC Class Codes: H04B 10/548 Phase or frequency modulation
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0298 with sub-carrier multiplexing [SCM]

Abstract

In one embodiment, a system includes at least one tone generator, a first transmitter, and a second transmitter. The at least one tone generator is operable to generate a plurality of modulation tones comprising at least a first modulation tone having a first tone frequency and a second modulation tone having a second tone frequency that is different from the first tone frequency. The first transmitter is operable to apply the first modulation tone to a first optical signal such that at least a portion of the first optical signal is divided into one or more sidebands. The second transmitter is operable to apply the second modulation tone to a second optical signal such that at least a portion of the second optical signal is divided into one or more sidebands.

Claims

1-20. -20. (canceled)

21. A system comprising:

at least one tone generator operable to generate a plurality of modulation tones, each modulation tone having a modulation frequency;

a plurality of transmitters operable to generate a plurality of modulated optical signals using the plurality of modulation tones and a plurality of information signals, each optical signal comprising a primary frequency; and

a wavelength multiplexer operable to multiplex the plurality of modulated optical signals into a single optical fiber;

wherein;

the modulation frequencies of the plurality of modulation tones comprise at least two different modulation frequencies; and

the modulation frequencies of the plurality of modulation tones are selected to reduce the ability of two-tone four-wave mixing (FWM) products and three-tone FWM products caused by the plurality of modulation tones to interfere with any of the primary frequencies of the plurality of optical signals.

22. The system of claim 21, wherein each of the modulation frequencies of the plurality of modulation tones is greater than the primary frequencies of the plurality of optical signals.

23. The system of claim 21, wherein selecting the modulation frequencies of the plurality of modulation tones to reduce the ability of two-tone FWM products and three-tone FWM products caused by the plurality of modulation tones to interfere with any of the primary frequencies of the plurality of optical signals comprises:

calculating frequencies of the two-tone FWM products and three-tone FWM products; and

determining whether the calculated frequencies of the two-tone FWM products and three-tone FWM products are within a predetermined distance from any of the primary frequencies of the plurality of optical signals.

24. The system of claim 21, wherein the primary frequencies of the plurality of optical signals are spaced at one or more selected distances apart to reduce the ability of one or more FWM products caused by multiplexing the plurality of optical signals into a single fiber to interfere with any of the primary frequencies of the plurality of optical signals.

25. The system of claim 21, wherein the plurality of modulation tones are suppression tones operable to suppress effects from stimulated Brillouin scattering (SBS).

26. A method comprising:

receiving a plurality of modulation tones from at least one tone generator, each modulation tone having a modulation frequency; and

generating a plurality of modulated optical signals using the plurality of modulation tones and a plurality of information signals, each optical signal comprising a primary frequency;

wherein;

the modulation frequencies of the plurality of modulation tones comprise at least two different modulation frequencies; and

the modulation frequencies of the plurality of modulation tones are selected to reduce the ability of one or more four-wave mixing (FWM) products caused by the plurality of modulation tones to interfere with any of the primary frequencies of the plurality of optical signals.

27. The method of claim 26, wherein the one or more FWM products comprises two-tone FWM products and three-tone FWM products.

28. The method of claim 26, further comprising multiplexing the plurality of modulated optical signals into a single optical fiber.

29. The method of claim 26, wherein selecting the modulation frequencies of the plurality of modulation tones to reduce the ability of one or more FWM products caused by the plurality of modulation tones to interfere with any of the primary frequencies of the plurality of optical signals comprises:

calculating frequencies of the one or more FWM products; and

determining whether the calculated frequencies of the one or more FWM products are within a predetermined distance from any of the primary frequencies of the plurality of optical signals.

30. The method of claim 26, wherein each of the modulation frequencies of the plurality of modulation tones is greater than the primary frequencies of the plurality of optical signals.

31. The method of claim 26, wherein the primary frequencies of the plurality of optical signals are spaced at one or more selected distances apart to reduce the ability of one or more FWM products caused by multiplexing the plurality of optical signals into a single fiber to interfere with any of the primary frequencies of the plurality of optical signals.

32. The method of claim 26, wherein the plurality of modulation tones are suppression tones operable to suppress effects from stimulated Brillouin scattering (SBS).

33. A system comprising:

at least one tone generator operable to generate a plurality of modulation tones, each modulation tone having a modulation frequency; and

a plurality of transmitters operable to generate a plurality of modulated optical signals using the plurality of modulation tones and a plurality of information signals, each optical signal comprising a primary frequency;

wherein;

the modulation frequencies of the plurality of modulation tones comprise at least two different modulation frequencies; and

the modulation frequencies of the plurality of modulation tones are selected to reduce the ability of one or more four-wave mixing (FWM) products caused by the plurality of modulation tones to interfere with any of the primary frequencies of the plurality of optical signals.

34. The system of claim 33, wherein the one or more FWM products comprises two-tone FWM products and three-tone FWM products.

35. The system of claim 33, further comprising a wavelength multiplexer operable to multiplex the plurality of modulated optical signals into a single optical fiber.

36. The system of claim 33, wherein selecting the modulation frequencies of the plurality of modulation tones to reduce the ability of one or more FWM products caused by the plurality of modulation tones to interfere with any of the primary frequencies of the plurality of optical signals comprises:

calculating frequencies of the one or more FWM products; and

determining whether the calculated frequencies of the one or more FWM products are within a predetermined distance from any of the primary frequencies of the plurality of optical signals.

37. The system of claim 33, wherein each of the modulation frequencies of the plurality of modulation tones is greater than the primary frequencies of the plurality of optical signals.

38. The system of claim 33, wherein the primary frequencies of the plurality of optical signals are spaced at one or more selected distances apart to reduce the ability of one or more FWM products caused by multiplexing the plurality of optical signals into a single fiber to interfere with any of the primary frequencies of the plurality of optical signals.

39. The system of claim 33, wherein the plurality of modulation tones are suppression tones operable to suppress effects from stimulated Brillouin scattering (SBS).

40. The system of claim 33, further comprising at least one dither generator operable to broaden the effective linewidth of the plurality of modulated optical signals by applying one or more dither signals.