New compensation scheme of magneto-optical current sensor for temperature stability improvement

Abstract

A novel magneto-optical current sensor (MOCS) with two sensing arms is proposed to improve the temperature stability. One of the arms, with a highly stable permanent magnet attached and orthogonal to the other one, is designed to provide a reference that follows the temperature characteristics of the sensing material. By a normalization operation between two arms, the temperature drift is compensated adaptively and a sensing output proportional to the measured current can be reached. A dual-input and dual-output structure is specially designed for the reference sensing arm to demodulate the DC Faraday rotation angle. This scheme compensates simultaneously two main temperature influence factors, the Verdet constant and linear birefringence. Validation tests were carried out and are discussed.

Research on the influence of temperature on the sensing function of Faraday effect optical magnetic field sensor

“…Furthermore, Cai et al [10] used quantum theory to consider the crystal field, effective field, and super-exchange effects to theoretically calculate the Verdet constant of the TGG crystal, further revealing the mechanism of temperature affecting the Verdet constant of paramagnetic magneto-optical materials. Since temperature has a significant effect on the Verdet constant of paramagnetic magneto-optical materials, most researchers use temperature compensation for the Verdet constant of magneto-optical materials to improve the temperature stability of the Faraday effect optical magnetic field sensor [11][12][13][14][15][16][17]. However, the sensing function is the key to determining the response characteristics of the sensor, and the Verdet constant is only one of the influencing parameters.…”