LiNbO3 optical waveguides deposited on sapphire by electric-field-assisted pulsed laser deposition

Oriented LiNbO3 films have been grown on sapphire (1 1 0 2) substrates by low electric-field-assisted pulsed laser deposition. KrF excimer laser (248 nm) has been utilized for the ablation of monocrystalline stoichiometric target. The deposition was performed at all substrate temperatures in the range of 550-800 degrees C in an oxygen atmosphere. The ablation threshold of 2.5 J/cm(2) for the monocrystalline target was determined from the experimental results presenting ablation rate vs. laser fluence dependence. Electro-optical properties of these films appeared to be strongly dependent on the process parameters (substrate temperature, oxygen partial pressure, electric field), demonstrating the importance of the epitaxial growth control during the deposition. The films structure and morphology were characterized by XRD and AFM, respectively. The waveguide properties of the films were studied experimentally. (C) 2000 Elsevier Science Ltd. All rights reserved.