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. 10, 2007
Filed:
Mar. 23, 2005
Atsushi Sakai, Kanagawa, JP;
Ikuo Katoh, Kanagawa, JP;
Hiroyoshi Funato, Kanagawa, JP;
Toshihiko Baba, Tokyo, JP;
Atsushi Sakai, Kanagawa, JP;
Ikuo Katoh, Kanagawa, JP;
Hiroyoshi Funato, Kanagawa, JP;
Toshihiko Baba, Tokyo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Toshihiko Baba, Tokyo, JP;
Abstract
An optical delay element including a photonic crystal line defect optical waveguide is disclosed that has a large group refractive index and has small or nearly constant wavelength dispersion of the group refractive index in a wide wavelength region for practical use. The optical delay element includes a line defect optical waveguide formed in a photonic crystal structure, and the volume of the line defect optical waveguide is less than the volume of a single line defect optical waveguide. Thereby, the waveguide band of the line defect optical waveguide has two zero points in the third order dispersion curve of the line defect optical waveguide, and the sign of the third order dispersion curve is inverted near the zero points. Therefore, the waveguide band of the line defect optical waveguide is modified, and this enables expansion of the wavelength region having a large group refractive index, small wavelength dispersion of the group refractive index, and small wavelength dispersion of the speed of optical pulses.