Improving thermal stability of LiNbO <sub>3</sub> based electro‐optical electric field sensor by depositing a TiO <sub>2</sub> film
She Wang, Hai Wang, Chanxiao Li, Chijie Zhuang, Rong Zeng
Abstract
Abstract Electro‐optic electric field sensors based on LiNbO 3 are widely used for the measurement of electric fields or transient voltages. However, the working bias of the sensor is influenced by the temperature due to the thermo‐optic effect of LiNbO 3 . An athermal electro‐optic electric field sensor was demonstrated by coating a thin layer of TiO 2 film which has a negative thermo‐optic coefficient, on the common‐path interferometer based sensor to compensate LiNbO 3 's positive thermo‐optic coefficient. Both calculation and experimental studies were conducted. The experimental results reasonably agree well with the calculated values, and the results show the sensor coated with a 640 nm thick TiO 2 film has a much smaller temperature dependence of 0.011°/°C compared to the initial value of 0.1°/°C.