How to use an acousto optic modulator (AOM modulator) as an optical switch
1. Background and technological development context
1.1 Origin of Laser: In 1960, Theodore Meiman invented the first practical ruby laser, marking the birth of laser technology.
1.2 Laser Development: Subsequently, various types of lasers emerged, such as gas lasers (such as helium neon lasers), semiconductor laser, and solid-state lasers (such as YAG lasers), gradually expanding their application scope to military, industrial, and medical fields.
1.3 Core requirement introduction: The laser needs stable power output, and in many applications, the laser cannot continuously irradiate the target. To avoid repeated switching of the laser itself, an external optical switch is introduced to precisely control the laser on/off.
2. Working principle of acousto optic modulator (AOM modulator)
AOM is an optical device that utilizes the acousto-optic effect, where sound waves propagate through a medium to form periodic refractive index changes, thereby modulating the characteristics of light waves passing through the medium, such as intensity, frequency, and direction. At present, the focus is on two diffraction modes:
1.1 Bragg diffraction: The most common is that light and sound waves form a specific angle, and the diffraction energy is mainly concentrated in the first-order light, similar to a stereo grating. This mode is mainly used for optical switch applications.
1.2 Raman diffraction: The direction of propagation of light and sound waves is perpendicular, and the diffracted light exhibits a multi-level symmetrical distribution, similar to a planar grating.
3. The working mode of AOM modulator as an optical switch
3.1 AOM does not load signal (does not work): The laser directly passes through (0-level light) and is absorbed by the reflection mirror in the optical path, with no effective output.
3.2 AOM loading signal (working): diffraction is generated, and the first-order light is emitted at a certain angle and enters the subsequent optical path for use.
By controlling whether the AOM modulator loads signals, fast switching and modulation of the laser can be achieved, meeting the application scenarios that require controlling the laser irradiation time.
In addition to being used as an optical switch, AOM can also utilize its two levels of light to generate interference and form optical beat signals, which can be used in measurement and other fields The practical demand for stable laser power output has given rise to optical switch technology, and acousto optic modulators (AOM modulator) are based on the principle and application of optical switch function using acousto-optic effects, especially the Bragg diffraction mode.
Post time: May-19-2026