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:
Jul. 02, 2019
Filed:
May. 19, 2017
Sharp Kabushiki Kaisha, Sakai, Osaka, JP;
The University of Tokyo, Bunkyo-ku, Tokyo, JP;
Teruhisa Kotani, Sakai, JP;
Yasuhiko Arakawa, Bunkyo-ku, JP;
SHARP KABUSHIKI KAISHA, Sakai, JP;
THE UNIVERSITY OF TOKYO, Tokyo, JP;
Abstract
A quantum cascade laser includes a semiconductor substrate and an active layer having a cascade structure, in which unit layered bodies, each composed of a quantum well light emitting layer and an injection layer, are stacked, wherein the unit layered body has a subband level structure having an upper laser level, a lower laser level, and a relaxation miniband composed of at least two energy levels with an energy spacing smaller than the energy difference (E) between the upper laser level and the lower laser level, the energy width of the relaxation miniband is smaller than the energy (E−E) obtained by subtracting the energy difference (E) from the energy (E) of longitudinal optical phonons, and electrons subjected to the intersubband transition are relaxed in the relaxation miniband and are injected into a quantum well light emitting layer in a subsequent unit layered body.