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:
Aug. 07, 2001
Filed:
Jun. 30, 1999
Marcel F. C. Schemmann, Echt, NL;
Venkatesh G. Mutalik, Manlius, NY (US);
Philips Electronics North America Corp., New York, NY (US);
Abstract
A method and apparatus for controlling and stabilizing laser wavelengths in a dense wavelength division multiplexer (DWDM) transmission system. The lasers in the transmission system are each modulated in a known manner by a data signal. In addition, the lasers are each modulated by a plurality of test signals each having a predetermined frequency. At the optical receiver, a frequency analyzer examiners the frequency test signals for distortions and/or changes in amplitude. Any distortions and/or changes in amplitude of the frequency test signals indicate a change in the wavelength of a corresponding laser. A control signal may be returned to the laser controller of each laser to regulate the laser wavelength. A fault signal may be generated indicating that the wavelength of a laser has changed, drifted, etc., more an acceptable amount.