Improving design method for sensitivity and frequency response of E-field sensor using a Mach-Zehnder interferometer

The design method for sensitivity and frequency response of an electric field sensor using a Mach-Zehnder interferometer (an optical E-field sensor) has been developed in order to measure electromagnetic environments and the performance of measuring facilities. The designs of the optical modulator, sensor elements, and sensitivity were analyzed theoretically by using an accurate equivalent circuit of the sensor. Then an actual sensor was fabricated, and its characteristics of the sensor were evaluated experimentally. The results show that the designed sensitivity and frequency response were optimal. The optical output deviation when the temperature increased from 0 to 40 degrees C was reduced to within 2 dB. The minimum detectable electric field strength was 17 dB mu V/m (8 mu V/m), and the dynamic range was more than 100 dB. The frequency response of the sensitivity was almost flat between 200 Hz and 900 MHz