| abstract |
The present invention is an optical isolator including a Faraday rotator including a trivalent ion exchange TAG (terbium-aluminum garnet), and narranged around the Faraday rotator, a central hollow magnet and a first and a second hollow magnet units arranged to sandwich the central hollow magnet in an optical axis direction, nwhere a magnetic flux density B [T] in the Faraday rotator and nan optical path length L [mm] where the Faraday rotator is arranged satisfy 0 < B nand 14.0 ≤ L ≤ 24.0 n This provides an optical isolator that, compared with a conventional Faraday rotator such as a terbium-gallium garnet (TGG) crystal, contributes to reduction of a thermal lensing effect, being a pending problem, in a high-output fiber laser. |