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. 01, 2009
Filed:
Oct. 31, 2006
Takashi Shiraishi, Kawasaki, JP;
Tetsu Hasegawa, Kawasaki, JP;
Masaharu Doi, Kawasaki, JP;
Kazuhiro Tanaka, Kawasaki, JP;
Takashi Shiraishi, Kawasaki, JP;
Tetsu Hasegawa, Kawasaki, JP;
Masaharu Doi, Kawasaki, JP;
Kazuhiro Tanaka, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
Optical waveguides (A) and (B) of a Mach-Zehnder modulator is normally formed on a −Z plane as an electric polarization non-inversion area. However, when the signal electrodeand the ground electrodeare provided asymmetrically on two waveguides, chirp occurs in output light, which is undesired. Therefore, these electrodes are provided symmetrically about the two waveguides. To effectively perform optical modulation, a part of the substrate in which an optical waveguide exists is to be electric polarization-inverted. As a result of the electric polarization inversion the optical waveguide is on the +Z plane. However, electric charge is accumulated on the +Z plane from unstable spontaneous electric polarization of an electric polarization inversion area, and has undesired influence on the performance of the optical modulator. Therefore, a conductive amorphous layer is formed on the surface of the electric polarization inversion area.