An electro–optic modulator (EOM) is an optical device in which a signal-controlled element exhibiting an electro–optic effect is used to modulate a beam of light. The modulation may be imposed on the phase, frequency, amplitude, or polarization of the beam. Modulation bandwidths extending into the gigahertz range are possible with the use of laser-controlled modulators. The electro–opti. Phase modulationPhase modulation (PM) is a modulation pattern that encodes information as variations in the instantaneous phase of a carrier wave. The phase of a carrier signal is modulated to follow th. A phase modulating EOM can also be used as an amplitude modulator by using a. This alternative technique is often used in where the requirements of phase stabi. Depending on the type and orientation of the nonlinear crystal, and on the direction of the applied electric field, the phase delay can depend on the polarization direction. A can thus be seen as a voltage-controlled.