3. Modulator

The schematic diagram of a magneto-optic modulator is shown in figure 8 . A constant magnetic field H _dc (a few hundred Oe) is applied perpendicular to the direction of light propagation. Parallel to this direction of propagation, a variable magnetic field H _rf (a few tens of Oe at low frequencies; of the order of Oe at microwave frequencies) modulates the magnetization by an angle ± θ and generates a time-modulated magnetization component. By Faraday rotation, this variation is then converted into amplitude modulation using an analyzer.