CA2589851A1 - Method and apparatus for reducing crosstalk and nonlinear distortions induced by raman interactions in a wavelength division multiplexed (wdm) optical communication system - Google Patents
Method and apparatus for reducing crosstalk and nonlinear distortions induced by raman interactions in a wavelength division multiplexed (wdm) optical communication system Download PDFInfo
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- CA2589851A1 CA2589851A1 CA002589851A CA2589851A CA2589851A1 CA 2589851 A1 CA2589851 A1 CA 2589851A1 CA 002589851 A CA002589851 A CA 002589851A CA 2589851 A CA2589851 A CA 2589851A CA 2589851 A1 CA2589851 A1 CA 2589851A1
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Abstract
A method and apparatus is provided for transmitting a WDM optical signal. The method begins by modulating a plurality of optical channels that are each located at a different wavelength from one another with (1) a respective one of a plurality of information--bearing electrical signals that all embody the same broadcast information and (2) a respective one of a plurality of RF signals having a common functional broadcast waveform, at least one of the RF signals being out of phase with respect to remaining ones of the plurality of RF signals. Each of the modulated optical channels are multiplexed to form a WDM optical signal. The WDM optical signal is forwarded onto an optical transmission path.
Claims (28)
1. A method of transmitting a WDM optical signal, comprising:
modulating a plurality of optical channels that are each located at a different wavelength from one another with a respective one of a plurality of information-bearing broadcast signals that all embody the same broadcast information, at least one of the broadcast signals being out of phase with respect to remaining ones of the plurality of broadcast signals;
multiplexing each of the modulated optical channels to form a WDM optical signal; and forwarding the WDM optical signal onto an optical transmission path.
modulating a plurality of optical channels that are each located at a different wavelength from one another with a respective one of a plurality of information-bearing broadcast signals that all embody the same broadcast information, at least one of the broadcast signals being out of phase with respect to remaining ones of the plurality of broadcast signals;
multiplexing each of the modulated optical channels to form a WDM optical signal; and forwarding the WDM optical signal onto an optical transmission path.
2. The method of claim 1 further comprising applying a phase shift of 180 degrees to said at least one of the plurality of broadcast signals relative to the remaining ones of the plurality of broadcast signals.
3. The method of claim 1 further comprising applying a phase shift to selected ones of the plurality of broadcast signals so that the optical channels modulated thereby have contributions to Raman crosstalk at a selected one of the optical channels that are diminished by contributions to Raman crosstalk from optical channels that do not undergo a phase shift.
4. The method of claim 1, wherein the step of modulating a plurality of optical channels further includes combining a narrowcast signal with each broadcast signal prior to modulating.
5. The method of claim 1 wherein the modulating further comprises:
shifting a phase of a first broadcast signal with respect to a second broadcast signal, wherein the first and second broadcast signals modulate optical channels at first and second optical wavelengths, respectively, such that Raman crosstalk and distortions are reduced at a third optical channel that is located at a third optical wavelength.
shifting a phase of a first broadcast signal with respect to a second broadcast signal, wherein the first and second broadcast signals modulate optical channels at first and second optical wavelengths, respectively, such that Raman crosstalk and distortions are reduced at a third optical channel that is located at a third optical wavelength.
6. The method of claim 1 wherein the modulating further comprises:
phase shifting of at least one of a plurality of broadcast signals that all embody the same information, wherein the phase shifted broadcast signal(s) and remaining non-phase shifted signals modulate optical channels at different optical wavelengths, respectively, such that Raman crosstalk and distortions are reduced at a optical channel that is predetermined at a optical wavelength.
phase shifting of at least one of a plurality of broadcast signals that all embody the same information, wherein the phase shifted broadcast signal(s) and remaining non-phase shifted signals modulate optical channels at different optical wavelengths, respectively, such that Raman crosstalk and distortions are reduced at a optical channel that is predetermined at a optical wavelength.
7. The method of claim 6 wherein a difference in wavelength between any of the optical channels is less than the maximum power transfer Stokes shift in the optical transmission path.
8. The method of claim 3 further comprising adjusting relative amplitudes of the first, second and third modulated optical channels to further reduce the Raman crosstalk.
9. The method of claim 4 further comprising adjusting relative amplitudes of the first, second and third modulated optical channels to further reduce the Raman crosstalk.
10. The method of claim 5 further comprising adjusting relative amplitudes of the first, second and third modulated optical channels to further reduce the Raman crosstalk.
11. The method of claim 3 further comprising adjusting relative laser polarization of the first, second and third modulated optical channels to further reduce the Raman crosstalk.
12. The method of claim 4 further comprising adjusting relative laser polarization of the first, second and third modulated optical channels to further reduce the Raman crosstalk.
13. The method of claim 5 further comprising adjusting relative laser polarization of the first, second and third modulated optical channels to further reduce the Raman crosstalk.
14. The method of claim 1 wherein the optical transmission path is located in a HFC
network.
network.
15. The method of claim 1 wherein the optical transmission path is located in a CATV
transmission network.
transmission network.
16. The method of claim 1 wherein the optical transmission path is located in a PON.
17. The method of claim 1 wherein the optical channels are located at wavelengths at or near a zero dispersion wavelength of the transmission path.
18. The method of claim 1 wherein the optical channels are located at wavelengths remote to a zero dispersion wavelength of the transmission path but dispersion impact is not significant.
19. A WDM optical transmitter, comprising:
a plurality of optical sources for generating optical channels located at different wavelengths;
a plurality of optical modulators each having an input for receiving a respective one of a plurality of information-bearing broadcast signals that all embody the same broadcast information, each optical modulator being associated with a respective one of the plurality of optical sources to thereby provide a plurality of modulated optical channels;
a phase shifter for adjusting a phase of at least one of the plurality of broadcast signals so that it is out of phase relative to another of the plurality of broadcast signals;
and a multiplexer coupled to the plurality of optical sources to receive and combine the modulated optical channels to produce a multiplexed optical signal.
a plurality of optical sources for generating optical channels located at different wavelengths;
a plurality of optical modulators each having an input for receiving a respective one of a plurality of information-bearing broadcast signals that all embody the same broadcast information, each optical modulator being associated with a respective one of the plurality of optical sources to thereby provide a plurality of modulated optical channels;
a phase shifter for adjusting a phase of at least one of the plurality of broadcast signals so that it is out of phase relative to another of the plurality of broadcast signals;
and a multiplexer coupled to the plurality of optical sources to receive and combine the modulated optical channels to produce a multiplexed optical signal.
20. The WDM optical transmitter of claim 19 wherein the phase shifter is configured to apply a phase shift of 180 degrees to said at least one of the plurality of broadcast signals relative to the remaining ones of the plurality of broadcast signals.
21. The WDM optical transmitter of claim 19 wherein the phase shifter is configured to apply a phase shift to selected ones of the plurality of broadcast signals so that the optical channels modulated thereby have contributions to Raman crosstalk at a selected one of the optical channels that are diminished by contributions to Raman crosstalk from optical channels that do not undergo a phase shift.
22. The WDM optical transmitter of claim 21 wherein the phase shifter is configured to shift a phase of a first broadcast signal with respect to a second broadcast signal, wherein the first and second broadcast signals modulate optical channels at first and second optical wavelengths, respectively, such that Raman crosstalk and induced distortions are reduced at a third optical channel.
23. The WDM optical transmitter of claim 22 wherein the plurality of optical sources are configured so that a difference in wavelength between any of the first, second, and third optical channels is less than the maximum power transfer Stokes shift in an optical transmission path into which the optical signal is to be transmitted.
24. The WDM optical transmitter of claim 22 further comprising an amplitude adjuster for adjusting relative amplitudes of the first, second and third modulated optical channels to further reduce the Raman crosstalk.
25. The WDM optical transmitter of claim 22 further comprising a light polarization adjuster for adjusting relative light polarization of the first, second and third modulated optical channels to further reduce the Raman crosstalk and induced distortions.
26. The WDM optical transmitter of claim 19 wherein the optical channels are located at wavelengths at or near a zero dispersion wavelength of an optical transmission path into which the optical signal is to be transmitted.
27. The WDM optical transmitter of claim 19 wherein the optical channels are located at wavelengths remote from a zero dispersion wavelength of the transmission path into which the optical signal is to be transmitted.
28. The WDM optical transmitter of claim 19, wherein the plurality of optical modulators are configured to receive narrowcast signals which are combined with each broadcast signal prior to modulating.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US81035806P | 2006-06-02 | 2006-06-02 | |
| US60/810,358 | 2006-06-02 | ||
| US11/612,832 | 2006-12-19 | ||
| US11/612,832 US7271948B1 (en) | 2006-12-19 | 2006-12-19 | Method and apparatus for reducing crosstalk and nonlinear distortions induced by raman interactions in a wavelength division mulitplexed (WDM) optical communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2589851A1 true CA2589851A1 (en) | 2007-12-02 |
| CA2589851C CA2589851C (en) | 2012-06-19 |
Family
ID=38792332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2589851A Expired - Fee Related CA2589851C (en) | 2006-06-02 | 2007-05-23 | Method and apparatus for reducing crosstalk and nonlinear distortions induced by raman interactions in a wavelength division multiplexed (wdm) optical communication system |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2589851C (en) |
| MX (1) | MX2007006571A (en) |
-
2007
- 2007-05-23 CA CA2589851A patent/CA2589851C/en not_active Expired - Fee Related
- 2007-06-01 MX MX2007006571A patent/MX2007006571A/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| MX2007006571A (en) | 2008-12-08 |
| CA2589851C (en) | 2012-06-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20220301 |
|
| MKLA | Lapsed |
Effective date: 20200831 |