Determination of stress profiles in optical-fibre preforms

A computational technique is presented for the nondestructive determination of the radial, axial and tangential stress profiles in optical-fibre preforms. Optical retardation which arises as a consequence of the photoelastic effect is the basis for the technique. The stress profiles are obtained by first evaluating and then numerically differentiating indefinite integrals defined on the optical retardation profiles.