Acousto optic modulator (AOM) is generally used to change the intensity of incident laser outside the laser cavity (amplitude modulation AM). This can be simple on / off modulation for fast switching or variable level modulation to achieve intensity modulation. The modulation mode is determined by the type of RF driver and can be digital (on / off) or analog (sinusoidal, square wave, linear, random...). Generally speaking, the RF driver of AOM adopts a fixed frequency. The key parameter of AOM is rise / fall time, which defines the achievable "speed" or amplitude modulation bandwidth of modulation. The rise / fall time is proportional to the beam diameter in the modulator. Therefore, the diameter of the incident laser beam must be controlled in order to obtain a fast rise time. The AOM can be used as a shutter (cycling the switch according to the set frequency) or as a variable attenuator (dynamically controlling the intensity of transmitted light). The laser modulation is realized by controlling the radio frequency to cause the acoustic wave in the acousto-optic crystal.

ModuOptik has developed a series of free space (single channel to up to 24 channels) and fiber-optic coupling (polarization maintaining and non polarization maintaining) AOMs. The frequency range is currently up to 300MHz and the rise time is as low as 4ns. ModuOptik can provide AOM matched RF drivers, and corresponding RF drivers can be selected according to product specifications.