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:
Nov. 19, 2002
Filed:
Mar. 06, 2001
Manabu Shiozaki, Yokohama, JP;
Toru Iwashima, Yokohama, JP;
Masakazu Shigehara, Yokohama, JP;
Kiyotaka Murashima, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
This invention relates to a diffraction grating device having a refractive index modulation formed in an optical waveguide region in a predetermined region in the longitudinal direction of the optical waveguide. In the diffraction grating device, a refractive index modulation is formed in the core region in a predetermined region in the longitudinal direction of the optical waveguide. In this diffraction grating device, the optical period of the refractive index modulation is substantially constant, the phase of the refractive index modulation is inverted at a phase inversion portion, and the number of phase inversion portions is one or two. In this diffraction grating device, the absolute value of a parameter R (equation ( )) is smaller than . According to this invention, a diffraction grating device capable of shortening the region where the refractive index modulation is formed and flattening the reflectance characteristic in the reflection wavelength band is provided.