PURPOSE: To obtain the signal processing functions of an AND and an OR circuit, etc., using light source bodies by causing the diffraction and interference of controlled light waves and sound waves in plural groups in a closed space and coupling amplifying elements, etc., with the light waves, etc.

CONSTITUTION: When a control gate A admits light and a control gate B does not admit the light or when the gate A does not admit the light and the gate B admits the light, diffracting rod materials which are opposite from changes of the gates A and B are displayed on a fluorescent screen 5 and elements 61 and 62 are arranged on the light rod materials. When the elements 61 and 62 are completely excited, the elements 61 and 62 depend on the interval X of a center line, light wavelength λ, and narrow line width W. When the gates A and B admit the light at the same time, the light interference spectrum of the gates A and B is displayed upon the fluorescent screen 5 through the amplifying elements, etc., and the elements 61 and 62 are arranged on the light rod materials; when they are completely excited, the light interference spectrum depends upon a distance D between two narrow lines and light wavelength λ. Thus, the signal processing functions of the AND and OR circuits, etc., using the light source bodies are obtained.