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. 05, 2005
Filed:
Aug. 29, 2003
Ken Hashimoto, Yokohama, JP;
Manabu Shiozaki, Yokohama, JP;
Toshikazu Shibata, Osaka, JP;
Akira Inoue, Yokohama, JP;
Ken Hashimoto, Yokohama, JP;
Manabu Shiozaki, Yokohama, JP;
Toshikazu Shibata, Osaka, JP;
Akira Inoue, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
The present invention relates to an optical waveguide type grating element and others in structure for decreasing absolute values of chromatic dispersion occurring in selective reflection of each of signal channels in a reflection band. The optical waveguide type grating element is provided with an optical waveguide in which signal light containing a plurality of signal channels spaced at a channel spacing λpropagates, and a grating which is an index modulation formed over a predetermined range of the optical waveguide. Particularly, the optical waveguide type grating element has a transmittance of −20 dB or less for each of the signal channels in the reflection band, and has a reflectance of −20 dB or less for each of signal channels outside the reflection band. Furthermore, a deviation of a group delay time of each of the signal channels in the reflection band, which is caused by reflection in the grating, is 10 ps or less in a wavelength range of (λ−λ×0.375/2) or more but (λ+λ×0.375/2) or less, where λis a center wavelength of each signal channel.