There are 2 kinds of acousto optic modulators(fiber coupled aom), one is fiber coupled acousto optic modulator, the other is free space acousto optic modulator. Acousto-optic Modulator IR AOM is for IR lasers, such as 1064nm, 1550nm, and 2000nm . More about acousto optic aom modulator. Acousto-optical modulation of thin film lithium niobate waveguide devices