Abstract
A novel scheme on an optical sensor for the electric voltage, current and power by using only one crystal is proposed and experimentally verified. A simple analysis shows that the possible crystal groups for this principle are limited to 8 groups, which have the electro-optic effect, the optical activity and the Faraday rotation. The practical crystals for this scheme are quartz and BSO (bismuth silicon oxide, or sillenite). The BSO is the most suitable for this scheme, because it is easy to optical adjustment and because it has a good temperature stability. A simple experiment using a quartz and a BSO crystal has shown good agreement with the theory.
