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. 01, 2003
Filed:
Aug. 03, 1999
Junichi Kinoshita, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
In order to realize an optical functional device like a DFB laser in which the radiation mode loss is small and the threshold current is low even when high-order gratings easy to process are used, the gratings are configured to be asymmetric in its cross-sectional structure. Then, by partly varying the asymmetry (blaze angle) of the cross-sectional structure of the gratings along the cavity lengthwise direction, the cavity-lengthwise profile of radiation modes from the high-order gratings is controlled. It is also controlled by using a relationship between a phase shift of the gratings and the asymmetry. In a edge emitting DFB laser, by utilizing destructive interference among radiation modes, the radiation mode loss is reduced, and the threshold can be decreased. When a radiation mode is used as an output, the radiation mode can be reinforced to increase the output by utilizing constructive interference.