![]() Technology optical fiber sensor systems have been developed during the past fifteen years for the ![]() Using much of the same rapidly-developing The high speed digital communication of information. ![]() Optical fiber systems have been developed during the past twenty-five years for primary applications in Using optic bulk glasses and electro-optic hybrid sensing techniques. Linear birefringence in optical fibre current sensors and review the recent development in the area of current measurement Hence, in this paper, we will summarize the possible solutions for dealing with the stability problems associated with bendinduced The electro-optic hybrid current sensors are often constructed from a conventionalĬurrent Iransfonner interrogated with different electro-optic or fibre optic sensing schemes.Īmong these groups ofsensor, optical fibre current sensors have been discussed and reviewed by a number of scientists 1ģ. Respectively, and I is the electric current. Where N1 and NC the number of passes of the light through the solenoid and the number of turns of wire in the solenoid Ifthe medium is subject to the magnetic field Where V is the Verdet constant ofthe fibre core and 1 is the interaction length. Is based upon the so-called "Faraday magneto-optic effect", in which the polarization azimuth, 1F' a linearly polarized lightīeam propagating inside an optical material is rotated under the influence of a magnetic field, H, generated by the electrical In general, the principle ofthe operation ofthe first two types of sensors (iii) the OCS type using electro-optic hybrid devices. Sensors (OCS) employing optical fibre as their sensing elements, (ii) the OCS type using bulk glass to sense the current, and Sensing materials used, the optical current measurement devices may be categorized into three main groups: (i) optical current According to the sensing mechanism employed and the Sensing element to an opto-eletronic control/processing unit, used to launch a light beam into the optical fibre andĭetect/demodulate the modulated optical signal collected from the fibre. Methods which employ optical fibre, or bulk glass, or even electro-optic hybrid sensing elements have been explored andĪviable commercial product has not yet emerged, despite the considerable level of research that has been devoted toĪn opticai current sensor consists of an optical current sensing element which measures the integral of the magneticįield along a closed (or nearly closed) optical loop around the current to be measured, an optical fibre link which connects the Schemes based upon the use of an optical fibre as the sensing element were proposed as early as 1976, and a number of new Replace the conventional curient transformer (CT) used in power distribution 1 Although current measurement In recent years, a considerable research effort has been expended on the field of optical current measurement in order to The asymmetry of the gain peaks is found to be caused by the optical activity of bismuth silicate and is predicted by the theory. In order to model the experimental results the steady-state expression for the space-charge field is extended to two dimensions and the usually neglected piezoelectric effect is included in the analysis of the modulation of the refractive index by the presence of this field inside the crystal. Furthermore the experimental results showed that the (theta) dependent gain peaks differ in magnitude according to whether the crystal is rotated in an anti-clockwise or clockwise direction. Our results show that by having a non-zero value of (theta) the signal gain can be improved by a factor of two. By mounting a crystal of bismuth silicate, with faces cut parallel to the (001), (110) and (110) planes, in a rotating holder, measurements of two wave gain as a function of (theta), the angle between the electric field vector E 0 (in the direction) and the grating vector, K (in the (110) plane), have been made. The application of a voltage, V 0, across a photorefractive crystal in the presence of detuning is well known as a means of enhancing two-wave gain.
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