 Component for optical data transmission |
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| Image processing apparatus |
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| Process and recording media for continuous wave four-level, two-photon holography |
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| Process for the preparation of aryldimethyl(3-aryl-propyl)silanes |
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| Optical information storage on a bacteriorhodopsin - containing film |
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| Asymmetrical dyes with large two-photon absorption cross-sections |
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| Two-photon upconverting dyes and applications |
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| Two-photon or higher-order absorbing optical materials and methods of use |
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| Signalling system |
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Polarization mode dispersion compensation
| Details |
Inventors: Farley, Kevin Stuart; Epworth, Richard Edward; Watley, Daniel;
Assignee: Nortel Networks Limited (St. Laurent, CA)
Primary Examiner: Pascal; Leslie
Assistant Examiner: Payne; David C.
Attorney, Agent or Firm: Barnes & Thornburg
A method of compensating the polarisation mode dispersion (PMD) of an optical transmission path carrying clocked digital data traffic involves modulating the state of polarisation (SOP) of the light launched into the transmission path, and employing consequential frequency components in an electrical signal detected at the far end of the transmission path to regulate the birefringence of a polarisation state controller portion of a birefringent element inserted between the transmission path and the receiver's photodetector. The SOP modulation, when represented on a Poincare sphere, has an oscillatory rotational component at a frequency f.sub.1 about a first axis of the sphere and an oscillatory rotational component at a frequency f.sub.2 about a second axis of the sphere that is orthogonal to said first axis, and where f.sub.1.noteq.f.sub.2, f.sub.1.noteq.2f.sub.2, and f.sub.2.noteq.2f.sub.1. |
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DETAILED DESCRIPTION An object of the invention is to provide a method of PMD compensation using a polarisation controller in association with a variable DGD compensation element, but without having to have recourse to the use of more than one detector for generating a control signal for regulating the polarisation controller and the DGD compensation unit.
A further object of the invention is to provide a method of PMD compensation using a polarisation controller in association with a fixed DGD compensation element, the method affording the capability of relatively fast control response times.
These objectives are accomplished by arranging to modulate the polarisation state of light launched into the transmission path.
This modulation is of a form that, when represented on a Poincare sphere, has an oscillatory rotational component at a frequency f.
sub.
1 about a first axis of the sphere, and an oscillatory rotational component at a frequency f.
sub.
2 about a second axis of the sphere that is orthogonal to the first axis, and where f.
sub.
1.
noteq.
f.
sub.
2, f.
sub.
1.
noteq.
2f.
sub.
2, and f.
sub.
2.
noteq.
2f.
sub.
1.
Other features and advantages of the invention will be readily apparent from the following description of preferred embodiments of the invention from the drawings and from the claims.
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Optical Systems 
