Microscopic computer tomography measurement of nonaxisymmetrically distributed optical fiber refractive index

A nonaxisymmetrically distributed method for measuring the refractive index of an optical fiber is described. The light intensity distribution is observed with a microscope when an optical fiber is latterally illuminated by collimated light. The integrated refractive-index difference along the projective line is obtained by performing two integrations of the light intensity. The fiber is rotated, and the observation and calculations are repeated at each angle of rotation. The refractive-index pattern over the fiber cross section is reconstructed by computer tomography.<
>