PHOTOCHROMIC BEHAVIOR OF THULIUM-DOPED SILICA OPTICAL FIBERS

There has been a recent increase in interest in optical fibres which exhibit enhanced nonlinear behavior by vitrue of the inclusion of rare-earth ions in the silica host glass. Photochromic behavior in optical fibres has been observed previously, and photorefractive effects have been noted in rare-earth doped silicate and phosphate glasses. We report the observation of the photochromic effect in thulium (Tm**3** plus )-doped silica optical fibres.