VARIABLE FARADAY ROTATOR, AND VARIABLE OPTICAL ATTENUATOR USING THE SAME

摘要

PROBLEM TO BE SOLVED: To downsize and thin down a variable Faraday rotator and a variable optical attenuator, and also to downsize an array structure which comprises a number of variable Faraday rotators disposed in parallel to one another.;SOLUTION: The Faraday rotator, provided with a magnetooptic crystal 10, permanent magnets 14a, 14b which apply a fixed magnetic field vertical to an advancing direction of light passing through the magnetooptic crystal 10, and electromagnets 12a, 12b which apply a variable magnetic field parallel to the advancing direction of the light, has an elongated rod shape as a whole, wherein a structure of the electromagnets comprises a cylindrical yoke 16 with a coil 18 coiled around the rim thereof, the electromagnets are placed in such a way that they are opposite to at least one light transmission plane of the magnetooptic crystal so as to make the inside of the cylindrical yokes optical paths and the pair of permanent magnets are placed on both sides of the magnetooptic crystal so as to interpose it. For the purpose of constructing the variable optical attenuator, a polarizer is disposed on the incident side of the magnetooptic crystal and an analyzer is disposed on the emission side thereof.;COPYRIGHT: (C)2005,JPO&NCIPI