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. 13, 1996
Filed:
Aug. 16, 1993
Yasuji Seko, Kanagawa, JP;
Hiromi Otoma, Kanagawa, JP;
Nobuaki Ueki, Kanagawa, JP;
Hideki Fukunaga, Kanagawa, JP;
Hideo Nakayama, Kanagawa, JP;
Kiichi Ueyanagi, Kanagawa, JP;
Yasuhiro Shiraki, Tokyo, JP;
Fuji Xerox Co., Ltd., Tokyo, JP;
Other;
Abstract
In a semiconductor laser device according to the invention, a clad layer includes first clad layers, each of which has a greater band gap than an active layer and has a thickness of 0.003 to 0.3 .mu.m, and second clad layers each of which has a lower refractive index than the active layer, and the first clad layers are disposed nearer to the active layer than the second clad layers, respectively. In this structure, the first clad layers confine carriers in the active layer while the second clad layers confine the light in the active layer. Since each of the first clad layers is formed of a thin film, the carriers are hard to move outwardly from the active layer due to the tunnel phenomenon thereof and, even if the lattice constant thereof is slightly different, the first clad layer can be lattice matched to a substrate. For this reason, the materials of the second clad layers can be selected without taking into consideration the size of the band gap thereof. This makes it possible to reduce the oscillation threshold value current density of the laser as well as to improve the temperature characteristic of the laser.