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:
Jul. 14, 2009
Filed:
Oct. 05, 2006
Masaji Noguchi, Kawasaki, JP;
Tomohiro Ueno, Kawasaki, JP;
Masaji Noguchi, Kawasaki, JP;
Tomohiro Ueno, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An optical communication apparatus for controlling the operating point of an optical modulation unit appropriately. An adding unit adds a bias voltage and a pilot signal. An optical modulation unit modulates light by an electrical signal, performs further modulation by a signal from the adding unit, and outputs an optical signal. A monitor unit monitors the level of the optical signal and outputs a monitor signal. A reference signal output unit outputs a reference in phase with the pilot signal contained in the monitor signal. A synchronous pilot-signal detection unit performs synchronous detection of the monitor signal by using the reference. A synchronous noise detection unit extracts noise from the monitor signal and performs synchronous detection of the noise by using the reference. A control signal output unit subtracts the synchronous detection value of the noise from that of the monitor signal, and outputs a control signal.