| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize a small-sized, lightweight and inexpensive device. SOLUTION: This optical isolator contains a Faraday rotator which consists of a magnetized hard magnetic garnet thick film satisfying the relation of S1/2/t<=3.5, wherein S is the area where light enters and t is the thickness. Or, the isolator may have a Faraday rotator having an almost square face where light enters and satisfying a/t<=3.5, wherein a is the length of the side and t is the thickness. The hard magnetic garnet thick film material used for the Faraday rotator is grown by a LPE method using a SGGG crystal as the substrate and has the compsn. of (EuXHo2-XBi)(Fe5-yGay)O12, wherein x and y satisfy 0.7<=x<=1.1 and 0.6<=y<=1.2, with B2O3 and PbO concn. of <=3 wt.%. In the production process, the material is heat treated in an atmosphere of >=10% oxygen concn. while keeping the temp. to 700 to 1100 deg.C.</p> |
