Measurements of stress anisotropy in fiber preform: modification of the dynamic spatial filtering technique.
A system for measuring the ray deflection function and retardation function related to preform birefringence is presented. It enables determination of the refractive-index profile and its anisotropy as well as the stress components within the same cross section of a preform. The system can be easily switched from measurement of the deflection function to measurement of the retardation function by moving a single element. Exemplary results of measurements are given. We note that preform anisotropy induced by stress may bring about additional errors in measurements of the refractive index by nondestructive methods.
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Urbańczyk
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Pietraszkiewicz