Design of Novel Resonant Optical Voltage Sensor Based on Pockels Effect

Abstract

A novel resonant optical voltage sensing scheme based on Pockels effect with less optical elements is proposed to pave the way for the miniaturization of voltage sensors in a high-voltage power grid, which can improve the voltage detection accuracy by using the multiple propagation of light in the resonator composed of Bi4Ge3O12 (BGO) crystal and reflector. Based on the multiple beam interference theory, the optical sensing model is analyzed to explore the influence of the key parameters such as the propagation loss and the resonator reflectivity on the performance of resonant optical voltage sensor. Considering the propagation loss and reflectivity, a resonator is designed to promote the limit sensitivity of the resonant optical voltage sensor. Also, based on the theoretical analysis results, we obtained that the design parameters (propagation loss <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> and reflectivity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${r}$ </tex-math></inline-formula> ) of the resonator are, respectively, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \le0.5$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${r} \ge0.83$ </tex-math></inline-formula> . Finally, the experimental equipment of the novel resonant optical voltage sensor is built, and the measured resonator finesse shows that the limit sensitivity of the resonant optical voltage sensor can achieve <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.689\times 10^{-{5}}$ </tex-math></inline-formula> V. Furthermore, the experimental results of the resonant optical voltage sensor demonstrate that the resonant frequency of the resonator is linear with the applied voltage. The proposed resonant sensing scheme has the potential to lay the foundation for the miniaturization of high-precision optical voltage sensors in the future.