Temperature dependence of the refractive index of strontium titanate and prism coupling to lithium niobate optical waveguides

The temperature dependence of the refractive index of SrTiO3, near room temperature, has been found to be −5.1×10−5 °C−1 at 632.8 nm by a variation of the minimum deviation prism method. We found that this temperature dependence had to be included to account correctly for the observed temperature sensitivity of coupling light to lithium niobate optical waveguides with strontium titanate prisms.