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. 18, 1992
Filed:
Mar. 11, 1988
Hideaki Tsushima, Hachioji, JP;
Katsuyuki Imoto, Sayama, JP;
Hirohisa Sano, Kokubunji, JP;
Akihiko Takase, Tokyo, JP;
Yoshitaka Takasaki, Tokorozawa, JP;
Minoru Maeda, Nishitama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An optical receiving method utilizing polarization diversity is disclosed in which first and second reference lightwaves having different frequencies and having polarization planes substantially perpendicular to each other, are combined with a signal lightwave to form a combined lightwave. The combined lightwave is subjected to heterodyne detection to obtain a detection signal and the detection signal is separated into first and second intermediate-frequency signals having different carrier frequencies. The first and second intermediate-frequency signals are converted into first and second baseband signals, respectively, and the first and second baseband signals are added to obtain an output signal.