Structure and optical properties of sol–gel derived Gd2O3 waveguide films

Pure and rare earth doped gadolinium oxide (Gd2O3) waveguide films were prepared by a simple sol–gel process and dipcoating method. Gd2O3 was successfully synthesized by hydrolysis of gadolinium acetate. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study the thermal chemistry properties of dried gel. Structure of Gd2O3 films annealed at different temperature ranging from 400 to 750 8C were investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that Gd2O3 starts crystallizing at about 400 8C and the crystallite size increases with annealing temperature. Oriented growth of (4 0 0) face of Gd2O3 has been observed when the films were deposited on (1 0 0) Si substrate and annealed at 750 8C. The laser beam (l ¼ 632:8 nm) was coupled into the film by a prism coupler and propagation loss of the film measured by scattering-detection method is about 2 dB/cm. Luminescence properties of europium ions doped films were measured and are discussed. # 2004 Elsevier B.V. All rights reserved