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:
Apr. 27, 2004
Filed:
Apr. 08, 2002
Hiroyuki Koshi, Tokyo, JP;
Kazuhisa Kashihara, Tokyo, JP;
The Furukawa Electric Co., Ltd., Tokyo, JP;
Abstract
An optical multiplexer/demultiplexer includes first and second directional coupling portions in which first and second optical waveguides are provided to transfer a light between the first and second optical waveguides. Lengths of the first and second optical waveguides have a difference (&Dgr;L). A product between the difference (&Dgr;L) and a refractive index (n) of the first and second optical waveguides approximates a product between a cross-propagation wavelength (&lgr;2) and a value (N′) substantially equal to an integer (N), and a product between a through-propagation wavelength (&lgr;1) and the value (N′)±0.5. Power coupling ratio differences are at least approximately 1% and at most approximately 10%. Third power coupling ratios with respect to an average wavelength of the cross-propagation wavelength (&lgr;2) and the through-propagation wavelength (&lgr;1) are at least approximately 45% and at most approximately 55%.