Unprecedented highest electro-optic coefficient of 226 pm/V for electro-optic polymer/TiO₂ multilayer slot waveguide modulators.

We investigated the electrical properties and optical quality of two layers a titanium dioxide (TiO₂) selective layer and a sol-gel silica cladding layer for use as coating layers for nonlinear optic (NLO) polymers in electro-optic (EO) polymer/TiO₂ multilayer slot waveguide modulators. We used a simple ellipsometric reflective technique developed by Teng and Man to measure the electro-optic (EO) coefficients of poled thin films of an EO polymer in an EO multilayer device. The Pockels coefficient was enhanced up to 226 and 198 pm/V at wavelengths of 1.31 and 1.55 μm, respectively, when optimally poled with TiO₂ and a sol-gel silica cladding.