Bragg gratings in ternary SiO2 : SnO2 : Na2O optical glass fibers

Bragg gratings have been written in an optical fiber with a core made hom t ernary SiO2:SnO2:Na2O glass and a SiO2 cladding. The presence of Na2O allow s for higher concentrations of SnO2, which are believed to be responsible f or the photorefractive response of this composition. In these preliminary e xperiments significant refractive-index modulations, up to 6.2 X 10(-4), ha ve been achieved with a 248-nm excimer laser and a phase mask to write grat ings for reflectivity at similar to 1.5 mu m. The induced refractive-index changes show enhanced temperature stability, and there is no sign of any er asure up to temperatures exceeding 600 degrees C. (C) 2000 Optical Society of America OCIS codes: 060.2400, 060.2290, 050.2270, 160.5320.