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:
Apr. 22, 2014
Filed:
Dec. 25, 2009
Applicant:
Masatoshi Tokushima, Tokyo, JP;
Inventor:
Masatoshi Tokushima, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 6/26 (2006.01);
U.S. Cl.
CPC ...
Abstract
A wavelength filter includes a first waveguide with a transmission band of a predetermined basic mode and a second waveguide, arranged in at least one location of the first waveguide, with a transmission band whose cutoff frequency corresponds to a finite value included in the transmission band of the basic mode. A pair of optical couplers constituting a Mach-Zehnder interferometer is connected to the opposite ends of a filter unit including the first waveguide and the second waveguide. When a plurality of wavelength filters is cascaded, the wavelength filters can be each varied in terms of the cutoff frequency of the second waveguide.