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. 20, 2007
Filed:
Jun. 20, 2003
Applicants:
Keishi Takaki, Tokyo, JP;
Tomofumi Kise, Tokyo, JP;
Masaki Funabashi, Tokyo, JP;
Inventors:
Assignee:
The Furukawa Electric Co., Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
H01S 3/08 (2006.01);
U.S. Cl.
CPC ...
Abstract
A DFB semiconductor laser device includes a diffraction grating extending parallel to a laser cavity. The diffraction grating has ununiform structure wherein some of the corrugation patterns of diffraction grating are omitted periodically, the diffraction grating has different duty ratio between the area near the front facet of the laser cavity and the area near the rear facet, or the length of the diffraction grating is smaller than the cavity length and the width of the diffraction grating reduces in the vicinity of the rear end of the diffraction grating down to zero at the rear end.