Design and analysis of electro optic sensor by finite element method

Abstract

The paper presents design, development, and analysis of electro-optic sensor by using FEM. The electro-optic effect (Pockels effect) has been used for measurement of voltage of variable frequency where a lithium-niobate crystal, sandwiched between electrodes undergoes a change in its refractive index when subjected to applied voltage. Change in refractive index is converted to a corresponding change in intensity using polarimetric method to facilitate on line measurement. The intensity of the output light transmitted through the crystal changes as a function of the applied voltage. Therefore output voltage of the detector gives a measure of the voltage applied. Experimental work has been carried out to study the effect of sinusoidal and also pulse used as voltage sensor or field sensor with high and low applied voltage. Multielectrode configuration forms the basic structure of an electro-optic A/D converter where number of electrode is equal to the number of bits of the A/D converter. The nonlinearity of the electro-optic sensor is found as +0.97%. The maximum applied voltage is 150 V and the sensitivity is (0.02-0.04) volt/volt.