3719 Warren Avenue Bellwood,
Illinois 60104 USA






Acousto-Optic Products

Acousto-optic devices manipulate light by interfering with strain induced by acoustic waves in optical materials, enabling these interactions to modulate either its amplitude or frequency of laser beams.

Our selection of free space and fiber-coupled acousto-optic modulators and RF drivers offers something suitable to any specific application requirements. Please select from one of these products that best matches your specific need.


Tunable optical modulators (TOMs) are devices that use acousto-optic (AO) effects to alter light. Acoustic waves create strain in an optical medium which alters its refractive index, altering light intensity or phase; or both; this allows users to customize light beam intensity or phase. Acoustic waves may also be used to rotate its polarization; although this practice is less commonly practiced than intensification modification.

AO effect can typically be generated by coupling acoustic waves to an optical waveguide, creating a birefringent structure with two regions of different refractive indexes; one for the propagating acoustic wave and another for optical beam propagation. Once inside one of these index regions, both waves interact producing Raman-Nath or Bragg diffraction depending on frequency and interaction length between acoustic wave and optical beam respectively.

Many acousto-optic devices used in optical systems are bulk devices housed in environmentally stable packages that offer good resistance against humidity and temperature changes. There are, however, smaller fiber-coupled acousto-optic modulators known as Acoustic Optic Modulators (AOMs), used in applications like optical switches or laser beam deflectors; they’re commonly referred to as AOMs.

Important characteristics of an AOM include aperture size, wavelength range, center frequency, rise time, insertion loss and modulation bandwidth. Rise time refers to how quickly an acoustic wave travels across an optical beam which affects how fast the AOM can amplitude modulate an optical signal while modulation bandwidth refers to frequency at which its amplitude changes from 10%-90% of full power.

Tunable Filters

An acousto-optic tunable filter (AOTF) is an electro-optical device which electronically tunes the wavelength of an optical signal through applying an acoustic modulation. Consisting of birefringent crystals which alter their optical properties when exposed to an acoustic wave, an AOTF allows users to rapidly change the optical frequency across a broad range. With their rapid tuning ability and wide frequency tuning range capabilities, AOTFs make an invaluable asset in applications like wavelength division multiplexing/demultiplexing/spectroscopic analyses.

Tellurium dioxide and crystalline quartz are among the most frequently used materials for collinear acousto-optic filters, although other materials like lithium niobate or gallium phosphide could also be considered depending on specific application needs such as optical damage thresholds, transparency ranges or transverse acoustic mode frequencies.

Collinear acousto-optic filter arrays (AOTFs) work as birefringent filters to select an ordinary (normal polarization) and extraordinary acoustic mode through birefringent interactions; these orthogonal modes are then coupled by an AOTF at an acoustic wavelength equal to its Bragg wavelength for crystals.

An optical cavity created by an acousto-optic crystal transmits the desired acoustic mode to an output fiber, either single-mode fused silica or multimode optical fibers. By altering input acoustic modulation frequency, center wavelength of optical output can be tuned from 350 nanometers up to 850 nanometers; for greater sensitivity it may be necessary to employ more slender output fibers; in all-fiber confocal microscopy this was demonstrated.


Deflectors differ from modulators in that their operation must take place over an extensive frequency range (i.e. drive frequencies). As a result, their design process becomes much more complicated; one must account for variations in material density as well as any interactions with optical windows, leading to much smaller deflection angle ranges than with modulators.

An acousto-optic deflector is a type of acousto-optical device which sequentially deflects laser beams by altering their applied radiofrequency (RF). Acoustic-optic interaction in these devices consists of coupling light with sound at frequencies higher than laser wavelength. Phase of an acoustic wave that is nominally parallel to optical propagation direction of phase mismatch vector determines where diffracted beam will land; hence an acousto-optic deflector should only be driven at frequencies where this goal can be attained.

Acoustic-optic deflectors stand out by using shear-mode interactions that significantly lower acoustic velocity, as opposed to longitudinal mode interactions. As a result, these deflectors can be applied in applications that require ultrashort laser pulses such as multiphoton excitation scanning microscopy or laser micromachining.

Deflectors must be capable of handling a broad spectrum of radio-frequency (RF) frequencies and offering wide field-of-view scanning. In addition, they must be compatible with integrated optic platforms that contain many optical devices on a single chip. RP Photonics has developed two TeO2 deflector configurations optimized for two-dimensional scanning with the goal of eliminating midband second order degeneracy while mitigating chromatic dispersion issues associated with ultrashort laser pulses.

Bragg Cells

Optics information processing systems rely on devices that produce wide bandwidth acousto-optic (AO) Bragg cells, and this requires materials with both high figure of merit and low attenuation rates as well as crystals which can be sectioned with piezoelectric transducers, plus methods for selecting optimal material and crystal orientation combinations for any given bandwidth.

AO Bragg cell technology has advanced to a point that its performance is now determined primarily by the materials and their configuration. Fused quartz, tellurium dioxide and lithium niobate are among the most commonly used acousto-optic materials; development work for new infrared materials is currently under way. At any given frequency of sound waves travel in both directions [100] and [001], respectively.

Aim the incident optical beam at an acoustic wave at its Bragg angle for optimal light diffraction/scattering, as specified by its input data bits to generate this RF signal and produce this acoustic wave. Variant diffracted beams will transport this input data to its destination receiver who then decodes its transmission sequence.

Acoustic resonators are effective tools for acousto-optic modulation, and can be utilized in applications requiring fast amplitude modulation of laser light in single mode optical fibers operating between 1470nm to 1630nm wavelength ranges. Applications such as Q-switched fiber laser pulse picking and narrow line width laser measurements make fiber-coupled systems ideal. These acousto-optic resonators are typically constructed using an integrated acousto-optic bragg cell and an acoustic resonator cavity, often consisting of an optical waveguide deposited onto an optically birefringent crystal substrate such as LiNbO3, while an acoustic resonator comprises of an array of interdigital transducers 43 that have been placed onto this crystal; their spacing, step size, phase spacing, etc. determine their resonance frequency f.

Frequency Shifters

Utilizing the acousto-optic effect, these devices can amplitude modulate laser beams and shift their frequencies by a set amount, up or down depending on their angular sketch configuration. They’re commonly employed in Q-switching as well as telecom and spectroscopy applications for signal modulation purposes.

An AO modulator converts radio-frequency electric signals from its driver into acoustic soundwaves using a piezoelectric transducer attached to a crystal or other material that diffracts light, using vibrations at certain frequencies that cause periodic planes of expansion and compression in the crystal, acting like an acousto-optic phase grating to reflect laser beams in multiple orders diffractionally.

An acoustic signal created by vibrations of a crystal can also cause a Doppler shift in the frequency of a diffracted laser beam if its directional wave vector runs in an opposite direction to that of its source signal; hence this type of acousto-optic modulator is also known as an “AO Doppler Frequency Shifter.”

As opposed to other acousto-optic heterodyne detection methods, single mode fiber (SMF) frequency shifters offer several distinct advantages over their rivals in terms of driving power consumption and shift size due to their all-fiber design. Applications that use ultrasonic sensors include fine spectrometry, vector hydrophone detection of nanoparticles and optical communications. Their impressive performance, precision, stability and anti-interference properties make them highly sought after by customers looking for cost-effective and compact devices. Furthermore, their all-metal sturdy hermetic package design ensures high temperature stability and excellent mechanical shock resistance. We provide an array of acousto-optic devices based on different wavelengths and frequencies to meet the demanding requirements of advanced applications.
Scroll to Top