SIMPLIFIED INTERFERENCE MEASUREMENT OF THE REFRACTIVE-INDEX DISTRIBUTION IN THE SLICES OF PREFORMS AND WAVE-GUIDES - DESTRUCTIVE METHOD OF PLANE REFERENCE WAVE AND SOME OF ITS VARIANTS

A simplified interference measurement method of refractive index distribution in slices of both preforms and light waveguides is presented. Different variants simplifying the measurement were described. The measurement errors introduced by the accepted simplifications were analysed. Also, the interference measurement methods for determination of the refractive index differences between the coat of either preform or waveguide and the immersion liquid are described. A simplified method of thickness distribution in the given slice is presented. The proposed destructive measurement methods may serve as a controlling pattern for the nondestructive methods.