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:
Oct. 02, 1990
Filed:
Apr. 14, 1989
Applicant:
Inventors:
Toshiaki Tanaka, Kokubunji, JP;
Takashi Kajimura, Tokyo, JP;
Toshihiro Kawano, Ome, JP;
Yuichi Ono, Tokyo, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01S / ;
U.S. Cl.
CPC ...
372 45 ; 372 46 ; 357-4 ; 357 17 ;
Abstract
A high-power low-noise semiconductor laser device required for light sources for an erasable optical disc is a self-sustained pulsating semiconductor laser device in which an MQW structure is used for an active layer, and thus a kink output power and a light output power by which the self-pulsation is enabled are increased to 10 mW or more and noise is reduced. Another semiconductor laser device of a self-pulsation type has impurities that are doped in the active layer to reduce the self-pulsating frequency to obtain a low-noise characteristic even if higher optical feedback occurs. 259