Paralleling to the Faraday angle of rotation variable device and the variable optical attenuator null

摘要

PROBLEM TO BE SOLVED: To control a Faraday rotational angle uniquely with the direction of a current supplied to a coil (and further maintain the current without electric supply) and to control a light attenuation quantity uniquely with the direction of the current supplied to the coil.;SOLUTION: A Faraday rotational angle varying device is equipped with a magnetic yoke 12 which has two or more magnetic gaps 10 linearly arrayed along an optical axis and is made of a soft magnetic material on the whole, the coil 14 wound around a magnetic circuit corresponding to each of the magnetic gap, and a magnetooptic element 16 inserted into each magnetic gap, and controls directions of magnetic fields applied to the individual magnetic gaps with current directions of respective coils to vary a composite Faraday rotational angle. When the magnetic yoke is made of a semi-rigid magnetic material or a semi-rigid magnetic material and a soft magnetic material, the composite Faraday rotational angle is self-maintained without electric supply to the coils.;COPYRIGHT: (C)2007,JPO&INPIT