A Micro Electromagnetic Field Sensor Based On Pockels Effect

With the flourishing development of photonics in recent ten years,photonics devices and optical electric field measurement technology have attracted widespread attention.Optical electric field sensor has a broad and important application prospect in the field of electrical safety,strong electric field detection,antenna array and other fields.Compared with the traditional electric field detection sensors based on electricity,the novel Pockels optical electric field sensors,using non-metallic materials,are easy to miniaturization and reduce the size of the photoelectric sensor greatly.Optical electric field sensor can measure the electric field accurately,and the measured electric field won't be interfered.In this paper,we design a kind of micro electric field sensor based on Pockels electro-optical effect,which integrate non-metal devices together,realize the miniaturization and integration of electric field measurement devices.We first analyze the principle of Pockels electro-optic effect and chose LiNbO3 crystal which has a large electro-optic coefficient and good stability.We introduce the ellipsoid model of refractive index of LiNbO3 crystal.Then analyze the advantages of reflective structure,design the micro reflective probe structure.We analyze the working principle of the probe with Jones matrix,and simulate the designed probe with COMSOL software.After that,we introduce the fabrication method and procedure of the probe in detail and present the finished probe,then test the insertion loss and stability of the finished probe.We test the finished micro probe in the low voltage electric field,power frequency electric field and the needle plate electric field.The results show that the sensitivity of the probe is 2V/m,the maximum detectable electric field intensity reach 3000V/mm.The probe has a good linearity and conform to the theoretical calculation.Through optimizing probe structure by numerical simulation can improve the stability of probe under different temperature and vibration.