Growth and characterization of lithium niobate planar waveguides by liquid phase epitaxy

Single crystal thin films of Yb, Zn:LiNbO₃ have been grown on LiNbO₃ substrates using liquid phase epitaxy with K₂ O flux. The segregation coefficients decrease abruptly at high doping concentrations, indicating a doping threshold. The surface roughness of the thin film increased with doping concentration. The propagation loss of the as-grown lithium niobate thin film sample was 0.154 ± 0.002 dB / mm at a wavelength of 1 μ m measured by the cutback method.