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:
Feb. 01, 2000
Filed:
Jul. 23, 1998
Applicant:
Inventors:
Michiko Harumoto, Yokohama, JP;
Toru Iwashima, Yokohama, JP;
Assignee:
Sumitomo Electric Industries, Osaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
385 37 ; 385 27 ; 385 28 ;
Abstract
A band-pass filter formed in an optical waveguide, provided with a diffraction grating group having a period .LAMBDA. of refractive index fluctuation changing in an axial direction with substantially a constant changing width .DELTA.n, comprises two periodic refractive index variable areas having periodes .LAMBDA. different from each other; a zero area, disposed therebetween, having substantially a constant refractive index; and boundary areas, disposed between the zero area and the respective periodic refractive index variable areas, in which the changing width of refractive index monotonously changes between 0 and .DELTA.n.