Elliptical polarization effects in a chromatically addressed faraday current sensor

G. D. Li*, Robin Aspey, M. G. Kong, J. R. Gibson, G. R. Jones

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Optical polarization processes in a parallel-sided glass element used in a Faraday rotation current sensor have been considered. In such sensors the path length necessary to produce sufficient rotation of the plane of polarization is produced by a multiplicity of reflections within the glass element. It is shown that such reflections induce ellipticity of polarization and that this affects the current-sensing performance of the sensor. Two reflection cases, corresponding to total internal reflections at a glass-air interface and reflections by aluminium-coated surfaces, are considered. The latter are shown to produce higher optical attenuation but a lower degree of elliptical polarization. The implications of the induced elliptical polarization in relation to chromatically modulated polychromatic light are considered. It is shown that the resolution of the Faraday sensing is improved by minimizing the ellipticity of the polarization with the aluminium-coated reflections. However a greater dynamic range and signal strength may be achievable with the total internal reflection element.

Original languageEnglish (US)
Pages (from-to)25-30
Number of pages6
JournalMeasurement Science and Technology
Volume10
Issue number1
DOIs
StatePublished - Jan 1 1999

Keywords

  • Current sensor
  • Electrical power system monitoring
  • Elliptical polarization
  • Faraday effect
  • Multiple reflection

ASJC Scopus subject areas

  • Instrumentation
  • Applied Mathematics

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