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:
Jan. 28, 1992
Filed:
Apr. 27, 1989
Takahiro Numai, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
An optical filter device comprises a distributed feedback region and an active region which are arranged in series and coupled optically, and anti-reflection structures which are positioned at both ends of the distributed feedback region and active region thus coupled to be in contact therewith so that a predetermined wavelength of an optical signal is selected from optical signals of, for instance, as much as 60 channels so that a wavelength selection can be performed in a narrow bandwidth of less than approximately 1 to 2 .ANG. and in a wide tuning range of an optical signal wavelength in accordance with a carrier injection thereinto.
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