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:
Aug. 08, 1978
Filed:
Mar. 09, 1977
Izuo Hayashi, Tokyo, JP;
Roy Lang, Tokyo, JP;
Nippon Electric Co., Ltd., Tokyo, JP;
Abstract
In an active layer restricted by a pair of heterojunctions in a semiconductor laser, a stripe region and a contiguous region are made to have a difference in kinds and/or concentrations of impurity to give the stripe region a higher dielectric constant, preferably by about 0.01-1%, than the contiguous region whereby transverse laser oscillation confined to the active layer by the heterojunctions is further confined to the stripe region in a width direction parallel to the heterojunctions. The dielectric constant profile established in the active layer stabilizes the transverse mode and eliminates nonlinearities in the laser output - exciting current curve as well as other undesirable performance characteristics that are exhibited in conventional stripe-geometry lasers. The difference in the impurity gives the stripe region a narrower band gap of from about 5 to about 100 meV than the contiguous region. For a laser of III-V-Group semiconductor materials, the difference is achieved by doping these regions with an n-type and/or a p-type impurity. The stripe width may be between about 1 micron and several tens of microns. The laser stably produces a single-mode optical output of 10 and 30 mW or more in CW and pulsed operation, respectively.