| 摘要 |
PURPOSE:To obtain a high isolation ratio by making the growing direction of a crystal of an optical isolator coincide with the optical axis direction of the optical isolator. CONSTITUTION:The growing direction of crystal used for an optical isolator is made coincide with the optical axis. A distortion by a composition variation which follows a growth fringe is generated due to a distortion in case when crystal layers having each different lattice constant have been superposed. A stress sigma is applied between the crystal layers having each different lattice constant, and a double refraction is generated through an optical elastic effect. Accordingly, when a light is made to pass through vertically in the crystal growing direction, a linearly polarized light becomes elliptical due to this double refraction, and deterioration of an extinction ratio is shown. In case when a light is made to transmit through in the crystal growing direction, a stress on the growth surface is generated uniformly, negated each other, and becomes a state that there is no stress equivalently, therefore, no double refraction is generated. |
