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:
Jul. 07, 1998
Filed:
Oct. 31, 1996
Richard Epworth, Sawbridgeworth, GB;
Duncan John Forbes, Bishops Stortford, GB;
Northern Telecom Limited, Montreal, CA;
Abstract
Method and apparatus for controlling the frequency of a laser in an optical transmission system which involves applying a frequency modulation to the laser, determining an amplitude modulation present in the signal downstream of the laser and attributable to the frequency modulation, and discriminating a portion of the amplitude modulation which is substantially in phase quadrature with the applied frequency modulation. The frequency of the laser is controlled on the basis of the discriminated quadrature portion. An optical component downstream of the laser may have a response which converts FM to AM. The response and the frequency output of the laser can be locked to one another, without errors caused by unwanted AM in the transmitted signal modulation frequency.