In telecommunication, electro-optics is the technology associated with those components, devices and systems which are designed to interact between the electromagnetic (optical) and the electric (electronic) state.

Note 1: The operation of electro-optic devices depends on modification of the refractive index of a material by electric fields.

Note 2: In a Kerr cell, the refractive index change is proportional to the square of the electric field, and the material is usually a liquid.

Note 3: In a Pockels cell, the refractive index change varies linearly with the electric field, and the material is a crystal.

Note 4: "Electro-optic" is often erroneously used as a synonym for "optoelectronic".

Source: from Federal Standard 1037C and from MIL-STD-188 and from the Department of Defense Dictionary of Military and Associated Terms