The highly sensitive optical measurement of absolute SAW amplitudes for power flow analysis

Author

Franke, Kurt ; Ross-Messemer, Martin ; Menck, Alexander ; Hoeller, Frank Stefan ; Schmidt, Hagen ; Weilmacht, M.

Author_Institution

Inst. fur Festkor per und Werkstofforschung, Dresden, Germany

Volume

50

Issue

1

fYear

2003

Firstpage

77

Lastpage

80

Abstract

The established optical method for the measurement of surface acoustic wave (SAW) amplitudes (simple probing) has been modified to result in the effective separation of scattered light from the SAW-diffracted light by means of two single mode optical fibers. In this way, the photodetector noise is drastically reduced, and absolute SAW amplitudes of 10/sup -12/ in can be detected easily. Using an additional precise measurement of the nondiffracted light by means of fiber shifting, the SAW amplitudes can be calibrated with an error of less than 3%. This method can be applied to deliver an accurate power flow analysis in SAW devices. As an example, for a YZ-LiNbO/sub 3/ transducer, the measured and calculated SAW power densities were found to agree within better than 6%.

Keywords

acoustic variables measurement; acousto-optical effects; light diffraction; optical fibres; surface acoustic waves; LiNbO/sub 3/; SAW amplitude; YZ-LiNbO/sub 3/ transducer; calibration; light diffraction; light scattering; optical measurement; photodetector noise; power flow analysis; single-mode optical fiber; Acoustic measurements; Acoustic waves; Fluid flow measurement; Load flow analysis; Optical noise; Optical scattering; Optical sensors; Optical surface waves; Power measurement; Surface acoustic waves;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/TUFFC.2003.1176527

Filename

1176527