Optical modulators convert information carried by an electric current in an electromagnet into light. According to the properties of the material that are used to modulate the light beam, modulators are divided into two groups: absorptive modulators and refractive modulators. The beam may be carried over free space, or propagated through an optical waveguide (optical fibre). The article explains how a Pockels cell within the modulator acts as a. Optical modulators are devices that modify the properties of light, such as its amplitude, phase, frequency, or polarization, in response to an external signal.