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:
Sep. 15, 1998
Filed:
Jul. 03, 1996
Shin'ichi Nakatsuka, Hino, JP;
Seiji Maruo, Hitachi, JP;
Shinya Kobayashi, Mito, JP;
Akira Arimoto, Kodaira, JP;
Susumu Saito, Hachioji, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
A semiconductor laser device is disclosed, in which two semiconductor layers of different conduction types are formed on a semiconductor substrate, an active semiconductor layer having a forbidden band width narrower than the two semiconductor layers is formed between the two semiconductor layers, and a waveguide encloses the light in a plane parallel to the active layer. The waveguide includes at least two regions of different widths. The wider one of the waveguide regions is located in the vicinity of the end surface of the semiconductor laser. A relation holds that .pi./6<L.times.(K.sub.0 -K.sub.2) <.pi..times.5/6, where L is the length of the wider waveguide region, and K.sub.0, K.sub.2 are propagation constants of the zeroth-order and second-order transverse modes, respectively, propagating in the waveguide.