Thermal variation of electric field sensor bias caused by anisotropy of LiNbO3

Abstract

Electric field sensors based on LiNbO3 are attractive for use in high-intensity transient electric field measurements. However, the working bias of such sensors is easily influenced by temperature variations. Many researchers have worked to improve the thermal stability of the bias of these sensors, mostly in terms of waveguide direction selection and suppression of the pyroelectric effect. In this letter, we present an analysis of the steady-state temperature stability of an x-cut, z-propagation, straight waveguide common-path interferometer-based sensor and show that the difference between the thermo-optic coefficients of no and ne caused by the anisotropy of the LiNbO3 crystal is the main factor that affects the steady-state working bias of the electric field sensor at different working temperatures. The experimental results for the changes in the sensor bias with temperature in the steady states are in good agreement with the theoretical analysis.