| 摘要 |
<p>PURPOSE:To measure an optical current and a magnetic field with high sensitivity, by using an oxide crystal whose Verdet constant is large, as an optical Faraday element. CONSTITUTION:Light emitted from an optical transmitter 1 is led to an optical sensor 3 through an optical fiber 2. When the light is converted to a parallel beam by a microlens 4 and is propagated in an optical Faraday element 9 consisting of an oxide crystal, if a magnetic field is applied in the advancing direction of the light, the polarized face of the light is Faraday-rotated. As for the oxide crystal, its Verdet constant being a performance index of a Faraday effect is large, comparing with lead glass, therefore, when it is used, the current and magnetic field detecting sensitivity can be improved. Also, a crystal belonging to a cubic system does not show natural double refraction essentially, therefore, its temperature characteristic is also good. In this way, by using an oxide crystal whose Verdet constant is large, as the optical Faraday element, an optical current and a magnetic field can be measured with high sensitivity.</p> |
