Measurement of temperature tuning coefficient of lithium niobate using nonlinear optical interferometry

A nonlinear optical interferometry based on second harmonic generation has been used to measure the temperature tuning coefficient of lithium niobate (or any birefringent crystal) directly and accurately. This method alleviates the need to measure refractive indices directly. The optical analysis is straightforward, shifting the major source of error to the temperature measurements. It is shown that the temperature tuning coefficent increases approximately linearly with increasing temperature. Different samples of lithium niobate are also compared.