Photonic Electric Field Sensing System (PEFS) is an instrument that optically measures the electric field. It integrates a fiber optic E-field sensor probe, a laser, a photo-receiver, an amplifier module, and associated electronics. The probe connects to the system via two fibers. The sensor system covers a broad frequency range from 10MHz to 40 GHz. The E-field intensity is proportional to the readout signal. The amplifier gains are adjustable to optimize the sensitivity and the dynamic ranges. The E-field frequency information can be obtained by connecting to a spectrum analyzer or a frequency-tunable filter. A multichannel system is available with the configurations of either switching among the sensor heads or simultaneously reading all heads at once using independent laser and detector sets. The fiber optic EOFS and PEFS form an E-field sensor system that provides advanced attributes of fast response, extremely high damage threshold exceeding 5MV/m, high fidelity with little disturbance to the E-field, and remote sensing capability.