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. 19, 2010
Filed:
Dec. 30, 2005
Yuichi Akiyama, Kawasaki, JP;
Takeshi Hoshida, Kawasaki, JP;
Yutaka Kai, Kawasaki, JP;
Hiroki Ooi, Kawasaki, JP;
Kentaro Nakamura, Kawasaki, JP;
Naoki Kuwata, Kawasaki, JP;
Yoshinori Nishizawa, Kawasaki, JP;
Tomoo Takahara, Kawasaki, JP;
Masahiro Yuki, Kawasaki, JP;
Yuichi Akiyama, Kawasaki, JP;
Takeshi Hoshida, Kawasaki, JP;
Yutaka Kai, Kawasaki, JP;
Hiroki Ooi, Kawasaki, JP;
Kentaro Nakamura, Kawasaki, JP;
Naoki Kuwata, Kawasaki, JP;
Yoshinori Nishizawa, Kawasaki, JP;
Tomoo Takahara, Kawasaki, JP;
Masahiro Yuki, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A phase shift unit provides a prescribed phase difference (π/2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal fis superimposed on one of the optical signals. A signal of which phase is shifted by π/2 from the low-frequency signal fis superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2fcomponent contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2fcomponent becomes the minimum.