| 摘要 |
PURPOSE:To lessen the deterioration in extinction ratio by a deviation in angle of a polarization plate by constituting the optical control device of an optical waveguide in which only the mode of either TM mode or TE mode is guided, metallic electrodes and a polarization plane maintaining optical fibers. CONSTITUTION:This waveguide type optical control device is composed of the optical waveguide which is formed on a substrate consisting of an anisotropic optical crystal and in which only the mode of either the TM mode or the TE mode is guided, the metallic electrodes for controlling the guided light formed on the optical waveguide and at least one piece of the polarization plane maintaining optical fibers arranged at one end of the optical waveguide in order to input and output the guided light. Then, the TE mode is approximately cut off, the ratio at which the TE mode component is excited is low and the modulation efficiency of the TE mode component is poor in the case of guiding with the TM mode even if the deviation in the angle of the polarization plane arises at the time of connecting the polarization plane optical fibers and the optical waveguide. Conversely, the TM mode is cut off, the ratio at which the TM mode component is excited is low and the modulation efficiency of the TM mode component is poor in the case of guiding with the TE mode. |
