Optical fiber stress-location measurement by synthesis of binary optical coherence function

A fiber-optic stress-location sensor by synthesis of a binary optical coherence function is proposed to locate a single stress event at a moment. The optical coherence function is synthesized into a "0-1" step along the fiber under test to judge in which half-section of the fiber the stress occurs. By shifting the edge of the "0-1" step to the middle of the half where the stress has been located, the stress location can further be specified to within a 1/4 section of the fiber. In this way, the stress location is determined with a distance resolution of 1/2/sup n/ of the fiber length by n judgments. Experimental results are presented.