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:
Oct. 27, 1987
Filed:
Jan. 21, 1983
Yasukazu Sano, Kanagawa, JP;
Fuji Electric Company, Ltd., Kanagawa, JP;
Abstract
An optical frequency filter for selectively blocking or transmitting an amplitude-modulated optical signal. In a first embodiment of the invention, an optical coupler adds two optical inputs. The output of the optical coupler is delayed and attenuated and then applied to the input of an optical splitter. One output port of the optical splitter is applied to one input port of the optical coupler, with the optical signal to be filtered applied to the other input port of the coupler. The filtered output signal is produced at the second output port of the splitter. In a second embodiment, the delay and attenuation are performed between the output of the splitter and the input of the coupler. In a third embodiment, the signal to be filtered is applied to the input port of an optical splitter. One of the output ports of the splitter is coupled through a delay to one input port of an optical combiner, while the other output port of the splitter is delayed and coupled to the other input port of the coupler.