JOINT TRANSFORM CORRELATOR FOR THE DETECTION OF DEFECTS IN OPTICAL FIBERS

A hybrid optical/digital system for detecting defects in optical fiber s is proposed. Since the structure of the fibers is the multilayer coa xial cylinder with step indices, the defects in any layer change the s patial frequency spectrum of the fibers and can be detected by compari son with the spectrum of a desired perfect fiber. A joint transform co rrelator can carry out the detection by continuously updating the test fiber with the desired reference fiber in its stationary position. We show that by joint transform correlator, fiber defects can be success fully detected. (C) 1998 Society of Photo-Optical instrumentation Engi neers. [S0091-3286(98)01305-1].