An electroabsorption modulator (or electro-absorption modulator) is a semiconductor -based optical modulator. It can be used for controlling (modulating) the intensity (more precisely: the optical power) of a laser beam via an electric voltage (→ intensity modulators). Its principle of operation is based on the Franz–Keldysh effect, i. In this section, we will explore the definition, historical development, and importance of EAMs in modern optical communication systems. When an electric field is applied to the active layer in the. Optical modulators use electrical signals to modify the physical characteristics of materials in such a way that the propagation conditions of light change.