We report on a thin-film channel waveguide electro-optic modulator fabricated in epitaxial BaTiO 3 on MgO. Films had an effective dc electro-optic coefficient of r eff ϳ50Ϯ5 pm/V and r eff ϳ18Ϯ2 pm/V at 5 MHz for ϳ1.55 m light. Extinction ratios of 14 dB were obtained. The electro-optic effect decreases to ϳ60% of the dc value at 1 Hz, 50% of the dc value at 20 kHz, and ϳ37% of the dc value at 5 MHz.

We report on the fabrication of channel waveguides in epitaxial grown BaTiO 3 layers on MgO. Layers were prepared by metalorganic chemical vapor deposition. Ridge waveguides with ridge heights ranging from 15 to 200 nm were fabricated in a 0.2-m-thick film. Single mode waveguide throughput, scattering loss, and mode profiles are reported. Coating waveguides with spin on glass significantly increase waveguide throughput. Throughputs of up to 10.4% were measured in 15 nm ridge waveguides which were 2.85 mm long and coated with spin on glass. Waveguide throughput is found to increase significantly with an increase in wavelength from 1.06 to 1.55 m.

BaTiO3 epitaxial films have been prepared on (001) MgO substrates by metalorganic chemical vapor deposition. The as‐deposited 0.2 μm thick films had a surface roughness of 12 nm. Channel waveguides were fabricated from the films and the optical throughput measured. To differentiate the surface scattering loss from the internal scattering loss, waveguides were also prepared with a surface planarization step to reduce the surface roughness to 2.5 nm. The waveguide loss was greatly reduced for the planarized waveguides. The results indicate that surface and side wall roughness accounted for the majority of the waveguide loss. Grain boundary grooving lead to surface roughness and routes to overcome this problem are discussed.

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