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:
Dec. 31, 2013
Filed:
Jan. 09, 2012
Katsumi Uesaka, Kanagawa, JP;
Tohru Watanabe, Kanagawa, JP;
Katsumi Uesaka, Kanagawa, JP;
Tohru Watanabe, Kanagawa, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
An optical modulation apparatus, including: a Mach-Zehnder optical modulator having two light waveguides, two output light waveguides, and a join-and-branch portion located therebetween; a drive circuit configured to output a modulation signal to modulation electrodes provided respectively on the two light waveguides as a differential signal, the modulation signal modulating lights propagated in the two light waveguides; a phase adjustment circuit configured to control first phase control signals to be output to phase adjustment electrodes provided respectively on the two light waveguides, and adjust phases of lights propagated in the two light waveguides; a phase shift control circuit configured to switch second phase control signals to be output to phase shift electrodes provided respectively on the two light waveguides, and change phases of the lights propagated in the two light waveguides; and a signal polarity reversal circuit configured to reverse a polarity of the differential signal.