Method of driving waveguide type optical device, and waveguide type optical device used in the driving method

摘要

PROBLEM TO BE SOLVED: To effectively prevent the acceleration of a drift phenomenon caused by a high voltage applied to a bias electrode or discharge breakdown of the bias electrode in a waveguide type optical element having the bias electrode.SOLUTION: The waveguide type optical element comprises: a substrate 100 having an electro-optical effect; two optical waveguides 104, 106 formed on the substrate; control electrodes 152, 154, 156 for applying electric fields of mutually opposite directions along the orientation of spontaneous polarization of the substrate to each of the two optical waveguides, and generating a difference in refractive index between the two optical waveguides. The placement of the control electrodes and/or the applied voltage to the control electrodes is (are) set so that the electric field intensity of an electric field that is in an opposite direction to the orientation of spontaneous polarization made to occur in the substrate by the control electrodes is smaller than the electric field intensity of an electric field that is in the same direction as the orientation of spontaneous polarization.SELECTED DRAWING: Figure 1