| 摘要 |
A polarization controlling apparatus is disclosed wherein the degree of freedom in apparatus design can be enhanced while increase of the power dissipation and increase of the apparatus scale are suppressed and a high-speed operation can be achieved. The polarization controlling apparatus includes a permanent magnet (2) itself or a permanent magnet to which a part capable of being magnetized is applied, an electromagnet (3) capable of changing the magnitude of a magnetic field to be generated thereby, and a Faraday rotation effect element (4), disposed at a position at which an interaction magnetic field produced by an interaction between a magnetic field generated by the permanent magnet (2) and a magnetic field generated by the electromagnet (3) acts, for producing a Faraday rotation effect on inputted light by means of the interaction magnetic field. The magnitude of the interaction magnetic field in the Faraday rotation effect element (4) is varied by a magnetic field component generated by the electromagnet (3) to vary the amount of the Faraday rotation effect to be had on the inputted light.
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