Abstract
He-Ne laser propagation in silica fiber after delivery of KrF excimer laser was experimentally investigated. The intensity at the outer part of deliveried He-Ne laser beam after delivery of KrF excimer laser was observed to be extremely reduced in comparison with that before delivery of KrF laser. We consider that this reduction results from the absorption of skew rays and/or the refractive index change at the outer part of core silica. It is supposed that these changes of optical property originate from the KrF-laser-induced defects located at the outer part of core layer.
