| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance the measuring accuracy by eliminating the effects of the offset drift of DC amplifier and the spontaneous polarization in inside crystal when a DC voltage is optically measured by using a crystal having an electrooptic effect. SOLUTION: Switches S1-S4 are connected to an optical crystal 1 having an electrooptic effect. A voltage to be measured Vx, which is applied to the crystal 1, is switched to the positive and negative values at the specified timing by these switches S1-S4. Then, the light, which is transmitted through the inside of the crystal 1, is received by a photodetector. The AC component in the output of the photodetector is taken out and amplified. The amplified output is rectified, and the DC detected voltage is obtained. At this time, the crystal 1 is once made to be in the short-circuited state at every time the applied voltage Vx is switched.</p> |
