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

Theoretical analysis of the temperature characteristics of an optical current sensing element

“…The effects of the peak wavelength shift of the optical source with temperature upon the output scale factor due to the dispersions of the linear birefringence, the reflection-induced-retardance and the Verdet constant of the sensing element were reported in references [13][14][15], respectively. Experiment showed that as temperature changes from 283 K to 303 K, the peak wavelength of the optical source changed from 1292 to 1302 nm.…”

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

“…Two critical factors that result in the temperature variation of MOCS are internal linear birefringence and Verdet constant of the sensing material [1]. Many compensation schemes have been designed to achieve excellent temperature stability [2][3][4][5][6] and most of them aim at weakening one of the effect factors instead of both. However, the MOCS accuracy must be better than 0.5% or even 0.2% in a wide operating temperature range from -25ºC to 40ºC [7], since it works in an outdoor power station and for measurement or protection purpose.…”

A novel design of the sensor head for avoiding the influence of the reflection phase shift in optical current transducer

“…In order to increase the sensitivity of BGOCT, some reflecting structures must be induced in the sensor head to make the linear polarized light transmit around the power line and form a long closed optical path. However, according to Fresnel formula, a phase shift between the p-and s-components of the light beam would be also induced during the total reflection, which is usually called reflection phase shift (or reflection-induced retardance) [5]. Such a reflection phase shift may change the linear polarized light into an elliptical polarized light [6] and degrade the measurement sensitivity and accuracy of the BGOCT.…”