OPTICAL ISOLATOR

PROBLEM TO BE SOLVED: To provide an optical isolator, facilitating optical axis adjustment while using a columnar Faraday rotator. SOLUTION: A wedge birefringent plate 12 is disposed on one side (the input side) of a 45-degree Faraday rotator 10, and a wedge birefringent plate 14 having a birefringent axis different from that of the birefringent plate 12 by 45 degrees is disposed on the other side (the output side). A cylindrical magnet 16 applies a magnetic field parallel to the direction of an optical axis 10a to the Faraday rotator 10. A prism 20 made of optical isotropic material is disposed outside the wedge birefringent plate 12, and a prism 22 made of optical isotropic material is disposed outside the wedge birefringent plate 14 as well. The prism 20 has an acute-angled apex angle on the opposite side to the wedge apex angle of the edge birefringent plate 12 with respect to the optical axis 10a. Similarly, the prism 22 has an acute-angled apex angle on the opposite side to the wedge apex angle of the edge birefringent plate 14 with respect to the optical axis 10a. COPYRIGHT: (C)2009,JPO&INPIT