Optical and structural analysis of Eu3+-doped alumina planar waveguides elaborated by the sol-gel process

Eu3+ ion-doped Al2O3 waveguiding thin films were dip-coated by the sol-gel route. Crack-free films were obtained, about 880 nm thick for 15 layers. According to the results of grazing incidence X-ray diffraction analysis and transmission electron microscopy (TEM), the film contains gamma -Al2O3 nanocrystals in an amorphous surrounding. The refractive index determined by m-lines spectroscopy is 1.582 at 543.7 nm. A good agreement between film thicknesses determined by m-lines spectroscopy measurements and TEM observation is obtained. The propagation is good (propagation losses less than 2 dB/cm) and waveguide fluorescence spectroscopy (WFS) could be used to register the Eu3+ fluorescence spectrum, which shows disordered environment for Eu3+ ions. (C) 2001 Elsevier Science B.V. All rights reserved.