Temperature dependence of a garnet-type optical current sensor

Abstract A garnet-type optical current sensor (OCS) is studied. Ta/Nd2Fe14B/Ta groove films are prepared on garnet by a magnetron sputtering method. The measurement errors of the Faraday rotation angle and the Verdet constant of the garnet-type and garnet-groove film OCSs are measured by Thorlabs polarimeters as a function of temperature. The results show that the measurement errors of the Faraday rotation angle of the garnet-type and garnet-groove film OCSs are 1.5% and 0.3%, respectively, when the current is 700 A at room temperature. The measurement error of the garnet-groove magnetic film OCS is lower than 0.3%, when the current changes from 0 to 1000 A and the temperature changes from 25 °C to 80 °C. The Verdet constant variations of the garnet-type and garnet-groove film OCSs cause different measurement errors when the temperature is changed.