Optical modulator and communications system

摘要

An optical modulator according to the present invention includes an optical waveguide 2 a to 2 d made of a material with an electro-optic effect and a modulating electrode 3 for applying a modulating electric signal to light propagating through the optical waveguide 2 a to 2 d. The modulator further includes a periodic structure, of which the equivalent refractive index changes periodically in a light propagation direction and which can reduce the group velocity of the light propagating through the optical waveguide 2 a, 2 b.