Preparation and characterization of sol-gel derived Er3+:Al2O3-SiO2 planar waveguides

Er3+ doped aluminosilicate thin films were prepared on silica and silica Si substrates by the sol-gel method. The Er ion concentration was varied from 0.25% to 1%. Fluorescences of Er ions in the visible and infrared regions were characterized. Green and red up-conversion fluorescences centered at 548 and 655 nm for, respectively, the (H-2(11/2) + S-4(3/2)) --> I-4(15/2) and F-2(9/2) --> I-4(15/2) were observed. A broadband peak was observed at 1531 nm corresponding to the I-4(13/2) --> I-4(15/2) transition, with the fun width at half-maximum of 47 nm comparable to those prepared by other methods. The fluorescence lifetime of the I-4(13/2), excited state was found to be constant and equal to 3.5 ms until a high Er doping of 0.5 at. %. (C) 1997 American Institute of Physics.