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:
Nov. 15, 2005
Filed:
Jan. 28, 2003
SI Hyung Cho, Silver Spring, MD (US);
Ilya Lyubomirsky, Columbia, MD (US);
Doyle Nichols, Ellicott City, MD (US);
Gerald Mcadoo, Silver Spring, MD (US);
Larry Davis, Columbia, MD (US);
Si Hyung Cho, Silver Spring, MD (US);
Ilya Lyubomirsky, Columbia, MD (US);
Doyle Nichols, Ellicott City, MD (US);
Gerald McAdoo, Silver Spring, MD (US);
Larry Davis, Columbia, MD (US);
Ciena Corporation, Linthicum, MD (US);
Abstract
The present invention is directed toward a laser wavelength locking scheme suitable for incorporation into WDM systems having channel spacings of 25 GHz or less. In a preferred embodiment, light output from the laser is supplied to a filtering element, such as an in-fiber Bragg grating or an etalon, and photodetectors are used to sense light transmitted through and either reflected by the filtering element or input to the filtering element. A measured ratio corresponding to a quotient of the photocurrents generated by the photodetectors is calculated and compared to a desired ratio corresponding to a measured temperature of the filtering element when the filtering element transmits the desired wavelength to be locked. Based on the comparison of the desired and measured ratios, a temperature error value is calculated which is used to adjust the laser temperature, as well as the laser wavelength. Accordingly, the temperature of the filtering element, for example, influences the laser temperature, so that wavelength variations stemming from temperature induced changes in the filtering element and other components in the laser package can be compensated, and the output wavelength can remain substantially fixed.