Method for detecting defects in fibers

摘要: Methods for deteting defects, such as, holes or voids, in optical waveguide fibers are provided. The methods employ far-field interference patterns produced by transversely illuminating the fiber with a laser beam. Holes produce characteristic peak spatial frequency spectrum of pattern which subdivides into two peaks migrate opposite directions as hole grows size. also increase total power pattern, amount being linear function size having diameter less than about 60% fiber. detection incorporated an overall system controlling drawing fibers.