| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical device having a polarization inversion region, of which the degradation in performance due to characteristics of the polarization inversion region is effectively prevented. <P>SOLUTION: Optical waveguides (A) and (B) of a Mach-Zehnder optical modulator are normally formed on a -Z plane being a polarization non-inversion region. Since chirp occurs in output light unfavorably when a signal electrode 11 and a ground electrode 10 are asymmetrically provided in two waveguides, these electrodes are symmetrically provided in two waveguides. In order to effectively apply optical modulation, polarization inversion of a part of an existing substrate of the optical waveguides is required. The optical waveguides are formed on a +Z plane by polarization inversion. However, electric charges are accumulated in the +Z plane because of instability of spontaneous polarization of the polarization inversion region to exert a bad influence upon performance of an optical modulator. Therefore, a conductive amorphous layer is formed on a surface of the polarization inversion region. <P>COPYRIGHT: (C)2012,JPO&INPIT |
