Current Monitor Using Elliptical Birefringent Fibre And Active Temperature Compensation

Abstract

Highly -elliptically birefringent fibres have been obtained by spinning a linearlybirefringent fibre during the draw. These fibres are particularly interesting for use in Faraday-effect fibre current monitors, since, in contrast with conventional fibres, they can be wound in small multi -turn coils and retain their sensitivity. We show that here the fibre output state of polarisation can be controlled to compensate for environmental perturbations using only one remote active element. Using a compact 80 -turn fibre coil, currents up to 370 A rms have been measured, with a maximum sensitivity of 100NA rms Hz-.

Magneto-optical fibre sensors for electrical industry: analysis of performances

“…However, further engineering efforts should be devoted to fibres and configurations least sensitive to vibrations and thermal perturbations, such as high elliptical or circular birefringence fibres and balanced or actively compensated configurations [41]. …”

Detection of plasma equilibrium shifts with fiber-optic sensing of image currents

“…[7] It achieves a predominantly circular birefrhgence fiber by extreme twisting during the drawing operation of an intentionally high linear birefringence fiber. The large temperature dependence of the high birefringence is compensated by averaging over many wavelengths, each of different birufringence, with a broad bancl diode laser light source, Furtherlnore the light is reflected from the far end back through the fiber to the entrance end.…”