NONDESTRUCTIVE METHOD FOR ATTENUATION MEASUREMENTS IN OPTICAL HOLLOW WAVE-GUIDES

A new method for characterizing hollow waveguides has been developed i n which the laser radiation is coupled into the waveguide hollow bore through an optical fiber. By moving the distal end of the fiber along the waveguide we achieved scanning of the incident radiation in the wa veguide at various points on the internal walls. This method can be em ployed for measuring attenuation without cutback or for detecting poin t defects on the waveguide's guiding layers.