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:
Aug. 28, 2001
Filed:
Dec. 14, 1999
Masayuki Nishimura, Kanagawa, JP;
Koji Nakazato, Kanagawa, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
The present invention is to provide a multi-channel variable optical attenuator with a small size and a simple control circuitry, which requires a short time for adjusting the attenuation level of signal lights. The optical attenuator comprises an optical attenuating portion,, a control circuitry,and a master control circuitry,. The optical attenuating portion includes a plurality of optical waveguides,and a plurality of attenuation adjusting portions,, both of which is formed in a substrate,. A signal light of a specific wavelength &lgr;,, which is derived from the wavelength multiplexed light, transmits in a respective waveguide,and is attenuated by a specific amount at the attenuation adjusting portion,. The control circuitry,outputs a plurality of control signals,to attenuation adjusting portions,so that the attenuation in each optical waveguides,is varied by the specific amount to the master control,sent from the master control circuitry,. Thus, optical output levels from waveguides,are equalized.