| 摘要 |
<p>PURPOSE:To accurately detect DC output voltage corresponding to a polarity of DC voltage to be measured by pulsating in timewise an electric field or voltage which are impressed on the medium having an electrooptic effect. CONSTITUTION:An output light with a constant intensity is emitted from a light emitting source 1 and made incident on an optical fiber 2 then guided to a polarizing element 4 after transmitting through a lens 27. The light subjected to linear polarization is then made incident on Pockels element 6 such as a BGO, etc., after subjected to circular polarization by a 1/4 wavelength plate 5. The DC voltage V to be measured is made to be ON/OFF in an electronic chopper circuit 13 and being impressed on the element 6 after pulsated. The circularly polarized light is changed to a ellipstically polarized light by this pulsated voltage, and after that, it is divided to orthogonally crossed two directional components by a photo detector 7 and each of them are conducted to opto-electric conversion circuits 10, 11 by optical fibers 8, 9. Since the same signal processing as one at the time of AC voltage measurement is performed for the output signal of this pulsated light in an arithmetic circuit 12, the DC components are entirely eliminated and the effect of DC is prevented.</p> |
