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. 11, 2006
Filed:
Aug. 13, 2004
Applicant:
Yuichiro Okunuki, Tokyo, JP;
Inventor:
Yuichiro Okunuki, Tokyo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01R 31/26 (2006.01); G01R 23/16 (2006.01); H01S 3/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
In testing a distributed feedback semiconductor laser with a grating having a phase shift part, a spectrum of the distributed feedback semiconductor laser is measured. A difference between an intensity of a side mode at a high-frequency-wave side of a main mode and an intensity of a side mode at a low-frequency-wave side of the main mode is calculated. The distributed feedback semiconductor laser is judged non-defective when the difference is more than a certain value.