Abstract

To operate electric power systems more securely and efficiently, a strong demand for fiber-optic voltage and current sensors is growing with recent progress in optical fiber technology.¹ In this work, we have fabricated a novel type of fiber-optic current sensor constructed of a magnetooptic Faraday rotator of Bi₁₂GeO₂₀ (BGO) single crystal with two thin-film polarizers. The BGO crystal was grown by the conventional Czochralski method. Measurement of its optical properties at a 0.85-μm wavelength indicated that the BGO crystal has not only a strong Faraday effect with a Verdet constant of 0.188 min/Oe cm but also optical activity with a specific rotation of 9.6 deg/mm. Therefore, the optical path length of the BGO Faraday rotator was determined to be 4.6 mm.

© 1983 Optical Society of America