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:
Jan. 28, 2003
Filed:
Aug. 26, 1998
Matsushita Electric Industrial Co., Ltd., Osaka-fu, JP;
Abstract
A branch portion branches an inputted electrical signal into an in-phase signal and an opposite phase signal which have an opposite relation as to a phase. A first FM laser converts the in-phase signal into an optical frequency-modulated signal (a first optical signal) having a center wavelength &lgr; and then outputs the resultant signal. A second FM laser converts the opposite phase signal into an optical frequency-modulated signal (a second signal) having a center wavelength &lgr; and then outputs the resultant signal. The two optical signals are combined and then inputted into an optical-electrical converting portion . The optical-electrical converting portion subjects the inputted optical signals to optical heterodyne detection by its square-law detection characteristic, and outputs a beat signal between the two optical signals which is a wide-band FM signal at a frequency corresponding to a wavelength difference &Dgr;&lgr;(=|&lgr; ) between the first optical signal and the second optical signal. It is thus possible to increase frequency deviation of the outputted FM signal and thus greatly improve a CNR.