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Journal of Sensors
Volume 2013, Article ID 650572, 7 pages
http://dx.doi.org/10.1155/2013/650572
Research Article

Growth and Characterization of Single Crystalline Bi4Ge3O12 Fibers for Electrooptic High Voltage Sensors

1ABB Switzerland Ltd., Corporate Research, Segelhof 1K, 5405 Baden-Dättwil, Switzerland
2ABB AG, Corporate Research, Wallstadter Straße 59, 68526 Ladenburg, Germany
3Fibercryst, S.A.S., La Doua-Bat L’Atrium, Boulevard, Latariet, 69616 Villeurbanne Cedex, France

Received 26 February 2013; Accepted 1 June 2013

Academic Editor: Kiyoshi Kurosawa

Copyright © 2013 Stephan Wildermuth et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The micro-pulling-down technique for crystalline fiber growth is employed to grow fibers and thin rods of bismuth germanate, Bi4Ge3O12 (BGO), for use in electrooptic high voltage sensors. The motivation is the growth of fibers that are considerably longer than the typical lengths (100–250 mm) that are achieved by more conventional growth techniques like the Czochralski technique. At a given voltage (several hundred kilovolts in high voltage substation applications) longer sensors result in lower electric field strengths and therefore more compact and simpler electric insulation. BGO samples with lengths up to 850 mm and thicknesses from 300 μm to 3 mm were grown. Particular challenges in the growth of BGO fibers are addressed. The relevant optical properties of the fibers are characterized, and the electrooptic response is investigated at voltages up to .