Improving Design Method for Sensitivity and Frequency Response of E-Field Sensor Using a Mach-Zehnder Interferometer

Thedesign method forsensitivity andfrequency response of anelectric fieldsensorusinga Mach-Zehnder interferometer (anoptical E-field sensor) hasbeendeveloped inorderto measure electromagnetic environments and the performance of measuring facilities.Thedesigns of theoptical modulator, sensorelements, andsensitivity wereanalyzed theoretically by usingan accurate equivalent circuitof thesensor. Thenanactual sensorwasfabricated, andits characteristics of thesensorwereevaluated experimentally. Theresultsshow thatthedesigned sensitivity andfrequency response wereoptimal. The optical outputdeviation when thetemperature increased from0 to40'C was reduced to within 2 dB. The minimum detectableelectric field strength was 17dBIlV/m (8IlV/m), and the dynamic rangewasmore than100dB.Thefrequency response of thesensitivity wasalmostflat between 200Hz and900MHz. key words: electric field sensor, antenna measurement, optical modulator, electro-optical effect, EMC