Electron-beam-induced densification of Ge-doped flame hydrolysis silica for waveguide fabrication

Experimentally we compare the densification induced by electron beam irradi ation of Ge-doped silica, produced by flame hydrolysis deposition with the densification of thermally produced SiO2. By comparing these results to the predictions made by elasticity theory, we find good agreement for the ther mal SiO2 by considering a single region of electron beam damage. For the Ge -doped flame-hydrolysis-deposited silica, we need to include in the model a second, shallow region, which densifies to a greater extent. X-ray photoel ectron spectroscopy measurements suggest that the thickness of this additio nal region is comparable to a layer that was found to be depleted of Ge. (C ) 2001 American Institute of Physics.