An optical waveguide 1, an optical waveguide 2 are formed on a substrate 3 to be crossed with each other, modulator electrodes 11, 12, 13 and 14 are arranged along the optical waveguides 1, 2, and antennas 21, 22, 23, 24 (i.e., square patch antennas having an approximately same shape) are arranged around four corners of the square shape. The modulator electrode 11 is energized from the antenna 21 and the antenna 22, the modulator electrode 12 is energized from the antenna 24 and the antenna 23, the modulator electrode 13 is energized from the antenna 21 and the antenna 24, and the modulator electrode 14 is energized from the antenna 22 and the antenna 23. The light wave propagating through the optical waveguide 1 is modulated by an electric field of Y-direction, and the light wave propagating through the optical waveguide 2 is modulated by an electric field of X-direction.