Patent
Optical transmission system including dispersion slope compensation
| العنوان: | Optical transmission system including dispersion slope compensation |
|---|---|
| Patent Number: | 7,295,728 |
| تاريخ النشر: | November 13, 2007 |
| Appl. No: | 11/363511 |
| Application Filed: | February 27, 2006 |
| مستخلص: | A WDM optical transmission system and method uses slope compensation at the transmit terminal and/or the receive terminal. The system and method may be used with modulation formats with a short pulse width and a broad optical spectrum. |
| Inventors: | Cai, Jin-Xing (Morganville, NJ, US); Foursa, Dmitri (Freehold, NJ, US); Davidson, Carl R. (Warren, NJ, US); Pilipetskii, Alexei N. (Colts Neck, NJ, US); Nissov, Morten (Ocean, NJ, US); Bergano, Neal S. (Lincroft, NJ, US) |
| Assignees: | Tyco Telecommunications (US) Inc. (Morristown, NJ, US) |
| Claim: | 1. A wavelength-division multiplexed optical communication system, compnsing: a transmitter configured to provide a plurality of optical signals, each of said optical signals having associated data modulated thereon and having a pulse width less than about 40% of a bit time associated with said data, said transmitter comprising: an optical signal source configured to generate at least one of said optical signals; a data modulator coupled to said optical signal source and configured to modulate said data on said at least one of said optical signals at a data modulation frequency; and an amplitude modulator coupled to said optical signal source and configured to provide a periodic modulation of the intensity of said at least one of said optical signals at an amplitude modulation frequency; a receiver: an optical fiber transmission path coupling said transmitter to said receiver, said transmission path establishing a end-to-end dispersion slope across a range of wavelengths transmitted from said transmitter to said receiver; and at least one dispersion slope compensator configured to compensate for at least a portion of said end-to-end dispersion slope, said at least one dispersion slope compensator being positioned at said transmitter or said receiver. |
| Claim: | 2. A system according to claim 1 wherein at least one of said optical signals has a pulse width less than about 31% of said bit time associated with said data. |
| Claim: | 3. A system according to claim 1 , wherein said data modulator is configured to modulate said data on said at least one of said optical signals using a DPSK modulation format. |
| Claim: | 4. A system according to claim 1 , said system further comprising an amplitude adjuster for selectively adjusting a depth of said periodic modulation of the intensity of said at least one of said optical signals. |
| Claim: | 5. A system according to claim 1 , wherein said amplitude modulator is configured to provide said periodic modulation at an intensity modulation depth equal to about 100%. |
| Claim: | 6. A system according to claim 1 , wherein said amplitude modulation frequency is equal to said data modulation frequency. |
| Claim: | 7. A system according to claim 1 , wherein said data modulation frequency is established by a clock coupled to said amplitude modulator. |
| Claim: | 8. A system according to claim 1 , wherein the amplitude modulator is configured to provide said periodic modulation of the intensity of said at least one of said optical signals with a prescribed phase. |
| Claim: | 9. A system according to claim 1 wherein said at least one dispersion compensator is positioned in said receiver. |
| Claim: | 10. A system according to claim 1 said system comprising a plurality of said dispersion compensators disposed in said receiver, each of said dispersion compensators being coupled for receiving at least one associated band of wavelengths for compensating for said end-to-end dispersion slope established across said associated band of wavelengths. |
| Claim: | 11. A system according to claim 1 said system comprising at least one transmitter dispersion compensator positioned in said transmitter and at least one receiver dispersion compensator positioned in said receiver. |
| Claim: | 12. A system according to claim 1 said system comprising at least one chromatic dispersion compensator configured to compensate for at least a portion of the magnitude of chromatic dispersion imparted to at least one of said optical signals by said transmission line. |
| Claim: | 13. A system according to claim 1 wherein said at least one dispersion slope compensator comprises an optical circulator comprising first, second and third ports, said first port being configured for receiving at least one of said optical signals, said second port being coupled to a fiber grating and being configured for receiving at least a portion of said at least one of said optical signals reflected from said fiber grating, and said third port being configured for providing said portion of said at least one of said optical signals as an output of said dispersion slope compensator. |
| Claim: | 14. A system according to claim 13 , said system further comprising a chromatic dispersion compensating fiber coupled to said first port and configured to compensate for at least a portion of the magnitude of chromatic dispersion imparted to said at least one of said optical signals by said transmission line. |
| Claim: | 15. A wavelength-division multiplexed optical communication system, comprising: a transmitter configured to provide a plurality of optical signals, each of said optical signals having associated data modulated thereon using a DPSK modulation format and having a periodic intensity modulation thereon at an intensity modulation depth equal to about 100% to establish a pulse width less than about 31% of a bit time associated with said data, said transmitter comprising an optical signal source configured to generate at least one of said optical signals; a data modulator coupled to said optical signal source and configured to modulate said data on said at least one of said optical signals at a data modulation frequency; and an amplitude modulator coupled to said optical signal source and configured to provide said periodic intensity modulation on said at least one of said optical signals; a receiver; an optical fiber transmission path coupling said transmitter to said receiver, said transmission path establishing a end-to-end dispersion slope across a range of wavelengths transmitted from said transmitter to said receiver; and at least one dispersion slope compensator configured to compensate for at least a portion of said end-to-end dispersion slope, said at least one dispersion slope compensator being positioned at said transmitter or said receiver. |
| Claim: | 16. A method of communicating wavelength-division multiplexed optical signals in a system including a transmitter for transmitting a plurality of optical signals to a receiver through an optical fiber transmission path, said optical fiber transmission path establishing an end-to-end dispersion slope across said optical signals, said method comprising: compensating for at least a portion of said end-to-end dispersion slope at said transmitter or said receiver; and modulating data on said optical signals with a pulse width less than a pulse width required to achieve a maximum Q-factor in the absence of said compensating step. |
| Claim: | 17. A method according to claim 16 , wherein said pulse width less than a pulse width required to achieve a maximum Q-factor in the absence of said compensating step is less than about 31% of a bit time associated with said data. |
| Claim: | 18. A method according to claim 16 , wherein said modulating comprises modulating said data on said optical signals using a DPSK modulation format. |
| Claim: | 19. A method according to claim 18 , said method further comprising transmitting said optical signals at a power level greater than that required to achieve a maximum Q-factor in the absence of said compensating step. |
| Claim: | 20. A method according to claim 16 , wherein said modulating comprises imparting a periodic amplitude modulation on said optical signals. |
| Claim: | 21. A method of improving the performance of an existing wavelength-division multiplexed communication system including a transmitter for transmitting a plurality of optical signals having data modulated thereon with an existing pulse width to a receiver through an optical fiber transmission path, said optical fiber transmission path establishing an end-to-end dispersion slope across said optical signals, said method comprising: compensating for at least a portion of said end-to-end dispersion slope at said transmitter or said receiver; and reducing said existing pulse width to a new pulse width less that required to achieve a maximum Q-factor in the absence of said compensating step. |
| Claim: | 22. A method according to claim 21 , wherein said new pulse width is less than about 31% of a bit time associated with said data. |
| Claim: | 23. A method according to claim 1 , said method further comprising increasing a power level associated with each of said optical signals. |
| Claim: | 24. A method of improving the performance of an existing wavelength-division multiplexed communication system including a transmitter for transmitting a plurality of optical signals having data modulated thereon with an existing pulse width to a receiver through an optical fiber transmission path, said optical fiber transmission path establishing an end-to-end dispersion slope across said optical signals, said method comprising: compensating for at least a portion of said end-to-end dispersion slope at said transmitter or said receiver; reducing said existing pulse width; and changing a modulation format for said data to a DPSK modulation format. |
| Claim: | 25. A method of improving the performance of an existing wavelength-division multiplexed communication system including a transmitter for transmitting a plurality of optical signals having data modulated thereon with an existing pulse width to a receiver through an optical fiber transmission path, said optical fiber transmission path establishing an end-to-end dispersion slope across said optical signals, said method comprising: compensating for at least a portion of said end-to-end dispersion slope at said transmitter or said receiver; reducing said existing pulse width; and imparting a periodic amplitude modulation on said optical signals. |
| Current U.S. Class: | 385/24 |
| Patent References Cited: | 6324317 November 2001 Tanaka et al. 7082234 July 2006 Lee et al. |
| Other References: | International Search Report and Written Opinion mailed Feb. 5, 2007 in connection with Applicant's corresponding PCT Patent Application. cited by other |
| Primary Examiner: | Doan, Jennifer |
| Attorney, Agent or Firm: | Grossman, Tucker, Perreault & Pfleger, PLLC |
| رقم الانضمام: | edspgr.07295728 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |