| 摘要 |
PROBLEM TO BE SOLVED: To provide a Faraday rotator which is a single crystal film of an iron garnet of a bismuth-substituted rare earth element having a specific chemical composition grown by a liquid-phase epitaxial method, suitable for an optical isolator. SOLUTION: This Faraday rotator is a single crystal film of an iron garnet of a bismuth-substituted rare earth element shown by a chemical composition of formula I ((x), (y) and (z) satisfy conditions of formula II) grown by a liquid- phase epitaxial method. The single crystal film has performances capable of miniaturizing an isolator for a semiconductor laser, about 750Oe saturated magnetic field, 0.06 degree/ deg.C temperature dependence of Faraday angle of rotation and provides 360μm to <=420μm thickness as a Faraday rotator at 1.55μm wavelength. The film thickness as the Faraday rotator, the saturated magnetic field, the Faraday rotation effect and the temperature characteristics are regulated to the excellent values by making the ratio of Ho/Tb, a bismuth substituted amount (y) and a Ga substituted amount (z) satisfy the conditions of formula II in the chemical composition. Usefully the single crystal is readily produced by a liquid-phase epitaxial method.
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