| 摘要 |
PURPOSE:To make the efficient change of refractive indices possible by the lower driving voltage by adopting layer structure in which superlattice layers are used and impressing the voltage to the superlattice layers. CONSTITUTION:This optical modulator is constituted by laminating repeatedly the 1st layers 1-1, 1-n and the 2nd layers 2-1, 1-n having the different refractive indices and using the superlattice layers consisting of extra-thin films (a), (b) consisting of different compsns. for the 2nd layers 2-1, 1-n. The repetitive period T thereof is made half the wavelength and the refractive indices are changed by applying the electric field to the superlattice layers. Light reflects at the boundary faces of the respective layers having the different refractive indices when the light is made incident through an upper transparent electrode 3 on the optical modulator of such multi-layered film type. The reflected light is intensified in the phase under certain condition and is weakened in the phase under the other condition.
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