Waveguides were written in Er-doped silica glasses by femtoscecond laser pulses. The waveguides exhibit a single mode at 632.8 nm with Gaussian profile and low propagation losses (<1dB over 4.8 mm). The optical properties like insertion losses and induced refractive index changes were measured and discussed. The optical gains at 1540 nm were measured as an active element in a standard waveguide amplifier setup. A maximum of 1dB internal gain at 200 mW, 976 nm pump were obtained.
Er-doped silica glasses (5000ppm Er/Si mol) were prepared by sol-gel method. Gel samples underwent dehydration in carbon tetrachloride environment. It shows that carbon tetrachloride can remove hydroxyl groups effectively. As a result, I13/2-I15/2 fluorescence lifetime rises considerably. It is also found that fluorescence lifetime is strongly dependent on OH concentration. For samples annealed in carbon tetrachloride at 900°C, fluorescence lifetime as long as 6ms was reached.