Influence of Growth Temperature on the Optical Properties of (YBi)3(FeGa)5O12 Film Waveguides

We report measurements of the optical properties of bismuth and gallium substituted yttrium iron garnet films deposited on GGG substrates by the LPE method for use as integrated optical waveguides. Emphasis is placed on the effect of the growth temperature. As the degree of supercooling was increased from 0.02 to 0.1 for a melt whose saturation temperature was 985°C, the refractive index of the film varied from 2.17 to 2.23 and the Faraday rotation varied from 200 to 800 degree/cm at a wavelength of 1.15 µm. However, the mode propagation loss was constant at nearly 10 dB/cm regardless of the growth temperature.