Single glass block faraday effect current sensor with homogeneous isotropic closed optical circuit

Abstract

A new scheme is proposed for achieving a closed, homogeneous, and isotropic optical circuit necessary for high-accuracy optical-current sensors. It makes use of a single solid polygonal solid with reflection surfaces coated by quarter-wavelength dielectric thin-film layers for the Faraday cell. We derive the design principle and show numerically its applicability in various Faraday materials. The cross talk with the surrounding current is investigated in particular detail both theoretically and experimentally. In the example experiment with a SF57 Faraday material, a low cross talk is demonstrated for nearby currents.

Joint effect of dispersions of reflection-induced retardance and Verdet constant upon the sensitivity of an optical current sensor

“…Eq. (8) shows that the Faraday rotation of the linearly polarized light is proportional to the following four factors: number of the optical paths circling the current N 1 , number of current carrying conductors passing through circling optical paths N 2 , the Verdet constant of the optical glass V , and current intensity to be measured I , which is usually considered as the principle of BGOCSs. The value of the Verdet constant is determined by some coe cients of the optical medium and the input wavelength are as given by [15] v…”

“…Many sensing schemes, such as "dual quadrature re ection", "critical angle re ection", "polarization-preserving total re ection" have been reported to reduce the harmful e ects of the re ection-induced retardance (RIR) upon the sensitivity of BGOCSs [1][2][3][4][5][6][7][8][9]. However, it was assumed that the output wavelength of the optical source was not changed in most of the research papers published and therefore the e ects of the dispersions of the optical devices upon the sensitivity of BGOCS systems were not considered.…”

Current measurement by Faraday effect on GEPOPU

“…The realization of a current sensor using bulk glass based on the Faraday effect has been widely studied [1][2][3][4][5][6][7][8][9]. The vast majority of optical configurations proposed are intended for use on high-voltage, highpower transmission lines.…”

Effect of the dispersion of the reflection-induced retardance upon the sensitivity of an optical current sensor

“…Many schemes, such as "dual-quadrature reflection", "critical angle reflection", "polarization-preserving totally reflection" etc have been reported to reduce the harmful effect of the reflection-induced retardance upon the sensitivity of BGOCSs [1][2][3][4][5][6][7][8][9] . However, it was assumed that the output wavelength of the optical source was not changed in most of the research papers published and therefore the effects of the dispersions of the optical devices upon the sensitivity of BGOCS systems were not considered.…”

“…According to from (3) to (7) and the experimental results of the optical source peak wavelength change reported in the section 2, we can obtain the dispersion curve of the reflected-induced retardance as shown in Fig.2 (8) to determine the values of the coefficients A and B in the formula, finally calculate out the refractive indices for the chosen 11 wavelengths (see Fig.2) from 1290nm to 1315nm using the formula with the determined values of the A and B. The Incident angle is °= α 45 0 for the calculation of the dispersion curve.…”