ENHANCED PHOTOSENSITIVITY IN TIN-CODOPED GERMANOSILICATE OPTICAL FIBERS

Enhanced photosensitivity is found in Tin-codoped germanosilicate opti cal fibers. A photo-induced refractive index change (similar to 1.4 x 10(-3)) 3 times larger than that observed in pure germanosilicate fibe rs has been demonstrated, Unlike the technique of using Boron-codoping to enhance the photosensitivity of germanosilicate fibers, Tin-doping does not have a significant effect on fiber loss at the important tel ecommunication window of 1.55 mu m. High temperature stability of the gratings in Tin-codoped germanosilicate fibers is also much over Boron -codoped fibers.