System and method for reducing Raman cross-talk in a DWDM transport system
US6236480A · kind A · utility
Inventor
Key dates
| Filing date | Jun 17, 1998 |
| Grant date | May 22, 2001 |
| Priority date | — |
| Expiry date | Jun 17, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J14/06
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A system and method for reducing Raman cross-talk between optical signals having different wavelengths in an optical communications system. Optical signals having wavelengths .lambda..sub.1, .lambda..sub.2, .lambda..sub.3, and .lambda..sub.4, respectively, are launched into an optical fiber at the headend of the system by an optical transmitter. Each wavelength .lambda. is preferably separated from each adjacent wavelength by the same amount, .DELTA..lambda.. .lambda..sub.1 and .lambda..sub.2 have vertical polarizations and .lambda..sub.3 and .lambda..sub.4 have horizontal polarizations. Because there is no Raman cross-talk between orthogonally polarized optical signals, there will be no Raman cross-talk between .lambda..sub.1 and .lambda..sub.3, between .lambda..sub.2 and .lambda..sub.4, between .lambda..sub.1 and .lambda..sub.4, or between .lambda..sub.2 and .lambda..sub.3. However, there is Raman cross-talk between .lambda..sub.1 and .lambda..sub.2 because each is vertically polarized and also between .lambda..sub.3 and .lambda..sub.4 because each is horizontally polarized. The amount of Raman cross talk is minimized because the wavelength difference between vertically polarized…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.