Growth of an epitaxial Bi₄Ti₃O₁₂/CeO₂/MgO heterostructure for waveguide applications

Using pulsed laser deposition, a Bi₄Ti₃O₁₂ thin film and Bi₄Ti₃O₁₂/CeO₂ heterostructures were grown on MgO(001) substrates. Structural properties of the film and the heterostructures were investigated using x-ray diffraction techniques. The heterosturctures were found to be more useful for making an optical single-mode waveguide, since it allows larger cut-off dimensions. By controlling the deposition temperature of the CeO₂ interlayer, an epitaxial heterostructure could be grown. From the epitaxial Bi₄Ti₃O₁₂/CeO₂/MgO heterostructure, a ridge waveguide was fabricated by photolithographic and ion-milling techniques. A single-mode near-field pattern was observed using an end-fire coupling method.