Pockels’ effect in polycrystalline ZnS planar waveguides

Abstract

The Pockels’ effect has been demonstrated in thermally evaporated polycrystalline thin films of ZnS. The strongly (111)-oriented films were found to have an electro-optic constant of r41 = 3.3 × 10−13 m/V for fields perpendicular to the (111) planes. Extinction ratios of up to 85% have been observed in an optical waveguide modulator. Analysis indicates a stress-related birefringence that manifests itself upon temperature change. The temperature coefficient of stress in the polycrystalline films was found to be 3.0×105 N m−2/°C.

Cold Deposition of Zinc Sulfide Optical Waveguides Using Thermoelectric Device

“…The high loss in polycrystalline ZnS waveguides are due to the combination of surface scattering and bulk scattering at the crystalline grain boundaries [3]. Therefore, a small grain size is necessary for a reduction of surface roughness and allows a reduction of the scattering [4]. Smallest grain size of ZnS can be found in its amorphous thin films and can be prepaid by depositing on the cold substrate.…”

The Propagation Losses of Cold Deposited Zinc Sulfide Waveguides

“…The high loss in polycrystalline ZnS waveguides are due to the combination of surface scattering and bulk scattering at the crystalline grain boundaries [3]. Therefore, a small grain size is necessary for a reduction of surface roughness and allows a reduction of the scattering [4]. Thermal depositions of dielectrics are well known for fabrication of anti-reflection coatings can also be used to produce ZnS waveguides.…”