Investigation of morphological effects of gamma irradiation on secondary coating surface of optical fibers by atomic force microscopy

The aim of this work is to investigate the morphological effect of gamma irradiation on the acrylic based secondary coating surface surrounding the cladding of the single mode optical fibers. 9 μm optical fibers (high grade pure silica) with 125 μm and 250 μm cladding and secondary coating in diameter respectively, have been irradiated with 60Co γ rays at a dose rate of 15 kGy/hour. A few micron scale images of the secondary coating surface have been acquired by Atomic Force Microscope (AFM) after 28, 59, 100 kGy exposure. In comparison with the unirradiated surface, roughness was observed to increase considerably as the dose increased. The number and sizes of the morphological changes arising as irregular hill like structures were analyzed from the height profiles with hill to trough differences in the order of 120 nm. (author)