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:
May. 13, 2003
Filed:
Feb. 16, 2000
Michiko Harumoto, Yokohama, JP;
Masakazu Shigehara, Yokohama, JP;
Shinji Ishikawa, Yokohama, JP;
Tadashi Enomoto, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
The present invention relates to a long-period grating device which eliminates only a desirable wavelength of core-mode light in a wavelength band in use from 1525 nm to 1610 nm. The long-period grating device according to the present invention comprises an optical fiber provided with a core region and a cladding region, whereas a long-period grating whose refractive index changes with a period &Lgr; in the advancing direction of light is provided in the core region, wherein the period &Lgr; is set such that the absolute value of a loss peak due to mode coupling concerning a refractive index modulation component with a period &Lgr;/(2n+1) (n=1, 2, 3, 4) is 0.2 dB or less in the wavelength band in use.