| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical isolator which aims simultaneously at a small- size, lightweight and low-price element using a Faraday rotator which does not require a permanent magnet for application of a magnetic field. SOLUTION: In this optical isolator, a Faraday rotator consists of a magnetized garnet thick film having 100 Oe or higher coercive force and 200 G residual magnetization. The ratio of the coercive force expressed in the Oe unit to the residual magnetization expressed in the G unit is 1.5 or higher. The garnet thick film is formed by a LPE method (liquid phase epitaxial growth) and essentially consists of the oxides of Gd, Bi, Fe, Al, Ga or the like.
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