A prism-coupler technique was introduced to determine the refractive indices and thermo-optic coefficients of epitaxial Sr0.6Ba0.4Nb2O6(SBN) waveguides, in a temperature range covering the ferroelectricparaelectric phase transition. A strong enhancement in the TO coefficient is observed near Tc. This strong enhancement is related to the critical change of the polarization. The values of/edn dT are significantly larger than/odn dT due to the larger quadratic electro-optic coefficient in TM polarization. In TM mode, the refractive index of SBN is increased by 1.3% as the temperature is increased to 160°C. Our results suggest that SBN waveguide is a potential candidate for thermo-optic modulators and switches.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics