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:
Jun. 02, 1992
Filed:
Jun. 13, 1990
Applicant:
Inventors:
Akihiko Oka, Kokubunji, JP;
Shinji Sakano, Hachioji, JP;
Naoki Chinone, Chofu, JP;
Tsukuru Ohtoshi, Kokubunji, JP;
Kazuhisa Uomi, Hachioji, JP;
Tomonobu Tsuchiya, Kodaira, JP;
Makoto Okai, Tokorozawa, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01S / ;
U.S. Cl.
CPC ...
372 50 ; 372 20 ; 372 33 ; 372 45 ; 372 46 ; 372 96 ; 372 98 ; 372102 ;
Abstract
A wavelength-tunable semiconductor laser device presenting a large wavelength-tunable range or a very-high-speed modulating semiconductor laser device having a distributed feedback structure including a diffraction grating as in the case of a DBR laser or a DFB laser incorporates therein a plurality of active layers differing from one another in constituent elements or composition ratio or thickness for reducing spectral line widths, while improving single-mode spectral oscillation characteristics.