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:
Feb. 25, 2003
Filed:
Mar. 13, 2000
Applicant:
Inventor:
Tetsuro Okuda, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01S 5/00 ; H01S 3/03 ; H01S 3/06 ; H01S 3/08 ;
U.S. Cl.
CPC ...
H01S 5/00 ; H01S 3/03 ; H01S 3/06 ; H01S 3/08 ;
Abstract
In a distributed feedback semiconductor laser having at least an active layer and a diffraction grating on a semiconductor substrate and so constructed that a current is injected uniformly over an axial direction of a resonator, a bandgap wavelength of the active layer in the neighborhood of a light outputting end or a backward end opposite to the light outputting end, is shorter than that in the other region of the active layer along the axial direction of the resonator.