Newsroom
What is an Electro-Optic Modulator (EOM)?
An Electro-Optic Modulator (EOM) is an active fiber-coupled or free-space optical device used to control the power, phase, or polarization state of a laser beam via an electrical drive signal. By utilizing materials that exhibit the linear electro-optic effect, an EOM acts as a high-speed interface between electronic systems and optical signals.
Its primary purpose is to convert high-frequency electrical data into optical formats, enabling ultra-fast switching, signal encoding, and precise laser control across telecom networks, optical sensors, and quantum platforms.
HOW an Electro-Optic Modulator (EOM) Works
The operation of an EOM is based on manipulating the refractive index of an optical crystal using an external voltage, following three logical steps:
Light Injection into an Anisotropic Crystal
A continuous-wave laser beam is launched into a precise optical waveguide embedded within an electro-optic crystal substrate, most commonly Lithium Niobate (LiNbO3).
Application of the Electric Field
An electrical signal (such as a radiofrequency or RF voltage) is applied to electrodes positioned alongside the waveguide. This creates an electric field that instantly modifies the crystal's physical refractive index—a phenomenon known as the Pockels effect.
Optical Modulation
As the light wave passes through this dynamically changing index zone, its velocity is altered. Depending on the internal design of the waveguide channel (such as a straight line for phase shifting or an interferometric split-and-recombine architecture for intensity variations), the exiting light emerges with its phase, amplitude, or polarization state modulated in perfect synchronization with the electrical input.
