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:
Nov. 27, 1979
Filed:
Oct. 19, 1977
Takashi Kajimura, Kokubunji, JP;
Kazutoshi Saito, Hachioji, JP;
Noriyuki Shige, Hachioji, JP;
Michiharu Nakamura, Tokyo, JP;
Jun-ichi Umeda, Hachioji, JP;
Masayoshi Kobayashi, Hachioji, JP;
Hitachi, Ltd., , JP;
Abstract
A semiconductor laser device capable of emitting highly collimated beams, especially of a narrow beam divergence, is disclosed. A striped hetero-junction is formed on a predetermined semiconductor substrate by a first semiconductor layer (refractive index: n.sub.1, band gap: Eg.sub.1, thickness: d), a second semiconductor layer (n.sub.2) and a third semiconductor layer (n.sub.3), and the hetero-junction is sandwiched between portions of a fourth semiconductor layer (n.sub.4, Eg.sub.4) into a buried structure. At this time, the various materials are selected to follow the relations of d.ltoreq..lambda. (where .lambda. denotes the oscillation wavelength of the semiconductor laser), n.sub.2, n.sub.3 <n.sub.4 <n.sub.1, and Eg.sub.1 <Eg.sub.4, and the effective refractive index of the first semiconductor layer (n.sub.1eq) is made smaller than n.sub.4.