Grating formation in pure silica-core fibers

Strong grating formation in pure silica-core fibers by use of 193-nm ArF-laser radiation is reported. Unsaturated refractive-index changes of Deltan similar to 0.3 X 10(-3) were observed in nontreated fiber, and changes of Deltan similar to 0.5 X 10(-3) were observed in fibers with a high hydroxyl concentration. Possible mechanisms of photosensitivity in pure silica-core fibers are discussed. (C) 2002 Optical Society of America.