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:
Jun. 01, 2004
Filed:
Nov. 19, 2002
Tadashi Takase, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a semiconductor laser which is modulation-doped in an active layer having a multiple quantum well structure, emission efficiency and modulation-band are improved. A semiconductor laser has an active layer between a p-type cladding layer and an n-type cladding layer. The active layer has multiple quantum wells with a plurality of barrier layers and well layers, and at least one barrier layer is p-type modulation-doped. More specifically, quantity of p-type modulation-doping of a barrier layer close to the p-cladding layer is smaller than of a barrier layer close to the n-cladding layer. Therefore, differential gain and high-speed response can be improved while suppressing nonluminous recombination. Since the concentration of holes is high in a well layer distant from the p-type cladding layer, the nonuniformity of carrier concentration can also be reduced.