A metal/semiconductor junction Schottky diode optical device using a distortion grown layer is described. A plurality of GaAs mirror and AlAs mirror layers are periodically grown on a semi-insulating GaAs substrate. An n+ or p+ semiconductor layer is formed on the GaAs mirror and AlAs mirror layers. A GaAs buffer layer is formed on the semiconductor layer to grow a Schottky metal layer serving as an electrode and a mirror. A multiple quantum well structure having an electro-optical absorption characteristic is positioned between the semiconductor layer and Schottky metal layer, for constructing a diode with the metal layer/multiple quantum well structure. At least a part of the mirror layers and diode are formed with a layer in order to have resonance and non-resonance conditions between the metal layer and mirror layers. The substrate on which the diode is formed has an opposite side formed with an optical non-reflective layer.