Error analysis for a Mach-Zehnder type speckle interferometer

A phase shifting speckle interferometer based on a Mach-Zehnder geometry is presented. The displacement field is measured using an electro-optic phase shifting technique. An analytical investigation of the accuracy of the interferometer is performed by considering the most contributing error sources. It is shown that in the case of the use of a low power laser source, the geometrical aberration of the optical component is the main contribution to the systematic errors. The case of the sampling of a full measurement is investigated. It is demonstrated that the systematic error of the full measurement has the same statistics as those given by a simple acquisition. Experimental results are reported in the case of the measurement of the deformation of industrial connectors submitted to a crushing test. It is found that for a peak to valley of 32µm, the trueness of the measurement appears higher than 160nm.