FLUORESCENCE LINE NARROWING IN ERBIUM-DOPED SILICA FIBERS

The properties of erbium-doped silica fiber amplifier are significantl y modified by the addition of only few percent of aluminum. For exampl e, at room temperature, the 1.5 mum emission line width is multiplied by a factor two. In order to improve our knowledge on rare-earth trans ition broadening mechanism, primarily in fibers, nonresonant fluoresce nce line narrowing measurements were performed on erbium-doped silica fibers codoped with either aluminum or germanium, at low temperatures. An important variation in site distribution and Stark splitting was f ound depending on the matrix.