| 摘要 |
PURPOSE:To eliminate the influence from the outside and to obtain stable characteristics by applying a magnetic field to be applied to a prism of a Faraday rotation material from a magnetic field generating part having magnetic poles provided oppositely in a closed magnetic path. CONSTITUTION:A yoke 7 is so formed as to form a closed magnetic field, and permanent magnets 8 and 9 are provided on the inner side thereof by opposing different magnetic poles. The light incident from an arrow S direction is polarized by a double refractive prism 11, is rotated 45 deg. by a Faraday rotator 10, is returned to the original by a 1/2 wavelength plate 12 and is emitted from a double refractive prism 13 to an arrow T direction. Conversely, the light incident from the T direction is polarized by the prism 13, is rotated 45 deg. of plane of polarization by the 1/2 wavelength plate and is further rotated 45 deg. by the Farady rotator to the light rotated 90 deg.. This light is intercepted by the prism 11. Thereby, the influence from the outside is eliminated, and the stable characteristics are obtained. |
