| 摘要 |
<p>A polarization controller comprises a plurality of devices (220, 230) connected in series to each other. Each device (220, 230) includes an optical channel waveguide (201) which is common to the plurality of the devices (220, 230), and an electrode (210) positioned on the optical channel waveguide (201) and two electrodes (211, 212) positioned on both sides of the optical channel waveguide (201). A retardation induced by electrooptic effect in each device (220, 230) is adjusted by voltages applied to the electrode (210) and the two electrodes (211, 212). The voltages are not kept increasing or decreasing, but changed periodically so that there is no limitation in an operating range for controlling a polarization of light which is propagated through the optical channel waveguide (201).</p> |
