Testing of Acousto-Optic Devices

The testing of acousto-optic (AO) devices is the step that follows the device fabrication and its main purpose is to determine the degree to which the design goals have been achieved. The full and precise characterization of an AO deflector requires several tests, which include acoustic echo measurements, Schlieren imaging, electric impedance, frequency response, scattering measurements, third-order intermodulation products, dynamic range, time-bandwidth product, and acoustic attenuation. One of the most critical steps in fabricating an AO device is the bonding of the transducer to the AO crystal. Following bonding, there are many steps in the fabrication procedure before the transducer structure is completed. High-performance AO processors require AO deflectors with uniform, well-collimated acoustic beams without acoustic reflections from the sides of the AO crystal and without beam walkoff. The electrical impedance and the return loss of an AO deflector can be easily measured via the use of a standard network analyzer.