Method and system for controlling polarization mode dispersion
US6583903B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 2000 |
| Grant date | Jun 24, 2003 |
| Priority date | — |
| Expiry date | Mar 2, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/2569
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In an optical data communications link, a modulated optical signal is emitted from an optical transmitter, coupled into one end of an optical fiber, and received by an optical receiver at the opposite end of the fiber. The present invention relates to reducing the polarization-mode dispersion (PMD) of the modulated optical signal caused by the birefringence of the fiber, which tends to limit the usable bandwidth of the fiber. A polarization controller is applied to the modulated optical signal substantially near the transmitter. The receiver measures the quality of the received signal and issues commands to the polarization controller to improve the received signal quality.In various embodiments, the signal quality measurement may be based on observed bit-error-rate (BER), estimated best attainable BER, or estimates of PMD affecting the received signal. Such measurements may be performed in the receiver by altering the threshold level and sampling timing of a bit detector in the receiver and monitoring the resulting changes in BER.Polarization control from the receiver are preferably coupled to the polarization controller through the same optical fiber carrying the modulated optica…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.