An Isotropic Electric-Field Sensing System Using Optical Probe

We design an isotropic electric-field sensing system using an optical probe. The optical probe consists of three electric-field sensors based on a Mach-Zehnder interferometer with the structure of segmented electrodes, which are perpendicular to each other. The measured results show that the ±5 dB baseband can reach 3 GHz, the linear dynamics range is 70dB, and the minimum detectable electric field is lower than 90 dBμ V/m （the spectrum analyser resolution is 100 Hz）. The directional characteristics are almost isotropic within deviations of ±1.5 dB. Therefore this sensing system can be used in the electromagnetic compatibility measurements.