The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 16, 2004
Filed:
Dec. 18, 2001
Nortel Networks Limited, St. Laurent, CA;
Abstract
Compensating for polarization mode dispersion in a birefringent optical transmission fibre is achieved by controlling the birefringence of the fibre. The difference in group velocity of the orthogonal polarization states of an optical signal transmitted over the fibre is monitored to generate an error signal representing the difference. The birefringence of the fibre is adjusted accordingly to minimize the difference and thereby provide dynamic compensation. Birefringence control may be achieved by a non-linear fibre grating written into the fibre to impose a differential time delay. The fibre may be a side hole fibre (SHF), a holey fibre (HF), a photonic crystal fibre (PCF), or any other suitable microstructure fibre. The fibre may have stressing rods, may be tapered along its length and may be controlled electrically, mechanically, acoustically or thermally by spaced heating elements.