| 摘要 |
PURPOSE:To prevent the impossibility of polarization control for the change of an optional polarization state by connecting three phase modulators, which generate pi/2-radian, pi-radian, and pi/2-radian phase differences respectively, successively in series in the direction of incidence. CONSTITUTION:Electrodes 101 are provided on four side faces of a square pyramid 100 having the electrooptic effect to form the first phase modulator 102. Similarly, square pyramids 100' and 100'' having the electrooptic effect and electrodes 101' and 101'' are used to form the second and third phase modulators 102' and 102''. End faces orthogonal to side faces where electrodes are provided of modulators 102, 102', and 102'' are butted and connected to one another. The light in an optional polarization state is converted to parallel rays of light and is propagated in modulators 102, 102', and 102'' successively. Proper voltages are applied to electrodes 101-101'' respectively to convert the light to a desired polarization state. By this constitution, the impossibility of polarization control due to continuous rise of the driving voltage is prevented even if the polarization state of an incident light is changed continuously in one direction.
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