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:
Jun. 08, 2004
Filed:
Jun. 21, 2001
Masaru Watanabe, Kawasaki, JP;
Eiji Matsuyama, Kawasaki, JP;
Akiyoshi Naruse, Kawasaki, JP;
Yuichi Murakami, Kawasaki, JP;
Kenichi Muta, Kawasaki, JP;
Toyomitsu Yamamoto, Kawasaki, JP;
Abstract
An optical attenuator which provides almost the same degree of attenuation even when the difference in wavelength of two different kinds of input optical signals is small. Another optical attenuator is provided with a dopant concentration in a technically realizable range which increases the difference in optical attenuation of two different kinds of input optical signals. Almost the same degree of attenuation may be obtained even when the difference between wavelengths is small by canceling the wavelength dependency of attenuation of the dopant by raising the refractive index of an axially central portion of the core as compared to that of the peripheral portion of the core and by taking into account the type and area of the dopant and the ratio of the difference &Dgr; between the refractive indexes of the cladding and the axial portion of the core and the difference &Dgr; between the refractive index of the cladding and the refractive index of the peripheral portion, i.e., &Dgr; . On the other hand, the difference of attenuation is increased while suppressing the concentration of dopant to the realizable range.