Faraday current sensor with temperature monitoring

Abstract

We present a novel optical current sensor based on the Faraday effect that incorporates a temperature monitoring system. The monitoring element is a temperature-dependent birefringent plate placed at the Faraday sensor head. Measurement of the plate retardation permits compensation for the temperature dependence of the Verdet constant. Validation experiments are presented and discussed.

Mitigation of Output Fluctuations due to Residual State of Input Polarization in a Compact Current Sensor

“…S out,ch2 =Pol(-90°). FR [β].Pol(+45°).S in (5) Whose intensities are the first elements, as Eq. (6) and Eq.…”

“…The design of optical sensors with two orthogonal polarization outputs allows, by means of the application of the difference-over-sum of the signals, the reduction of the effects of optical source instabilities as well as the effects of unwanted birefringence [1,3]. In [5] the use of a temperature-dependent birefringent plate in the Faraday sensor head allows, by the measurement of its retardation, the compensation for the temperature dependence of the Verdet constant. The use of multiple output ports and related signal processing was a recent reported advance in detection scheme [6].…”

Enhanced current sensitivity in the optical fiber doped with CdSe quantum dots

“…However, as reported, the bulk glass current sensors need bulk optical devices such as polarizers, birefringent plates, special launching lenses, which need precision alignment and careful handling [7,8].…”

“…Bulk glass current sensors [5] and their sensitivity improvement technique employing a ferromagnetic field concentrator has been earlier reported [6]. Bulk current sensors to sense high magnitude of current were realized by using the quartz glass [7] and in another research, simultaneous current and temperature sensing was carried out [8].…”

Compensation of Verdet Constant Temperature Dependence by Crystal Core Temperature Measurement

“…The temperature dependence of a Faraday medium has been identified as an important issue [7,8,9,10,11,12,13,14] requiring compensation in order for the sensor to attain the required level of precision. The choices of the Faraday crystal and the measurement technique are essential for maintaining the extrinsic FOCS advantages as well as for temperature compensation.…”