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. 02, 2011
Filed:
Mar. 28, 2008
Noriaki Mizuguchi, Kawasaki, JP;
Takashi Toyomaki, Kawasaki, JP;
Yoshikazu Terayama, Kawasaki, JP;
Kenichi Kaburagi, Kawasaki, JP;
Noriaki Mizuguchi, Kawasaki, JP;
Takashi Toyomaki, Kawasaki, JP;
Yoshikazu Terayama, Kawasaki, JP;
Kenichi Kaburagi, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An optical apparatus comprising: a branching unit branching an input light modulated by DQSPK format and thereby outputting a first branched light and a second branched light; a first branch and a second branch inputting the first branched light and the second branched light, respectively, the first branch and the second branch having an interferometer, a photo detector, and discriminator and demodulating I-signal and Q-signal, respectively; and an abnormality detection unit detecting an abnormality of the input light based on a synchronized detection of a first demodulated signal output from the photo detector in the first branch and a first recovered signal output from the discriminator in the first branch, and a synchronized detection of a second demodulated signal output from the photo detector in the second branch and a second recovered signal output from the discriminator in the second branch.