Temperature dependence of the thermo-optic coefficient of lithium niobate, from 300 to 515 K in the visible and infrared regions

The temperature dependence of the thermo-optic coefficients of lithium niobate has been measured in the temperature range between 320 and 515 K for both wavelengths of 632 and 1523 nm and for ordinary and extraordinary refractive indices. The experimental data, carried out by means of a simple interferometric technique, have been compared with two theoretical models that follow different approaches for treating the thermo-optic effect. The experimental results show good agreement with the theoretical ones.