| 摘要 |
PURPOSE:To obtain the optical switch which guides light inputted from one or two optical fibers to one of two other fibers by applying an external voltage to liquid crystal as an active medium. CONSTITUTION:The optical switch is provided with parallel light converting and converging lenses 4 and 5 for input light from optical fibers 8 and 9, a polarizing prism 2 which separate converted input light into P and S polarized light beams, and a liquid crystal cell which contains nematic liquid crystal having such dielectric constant dispersion as to change in type from P to N at specific driving frequency. Further, a voltage-frequency converter 19 is provided to generate a switching signal of frequency lower or higher than the transition frequency of the liquid crystal at the upper and lower limits of specific in-use ambient temperature corresponding to an on-off signal, thereby attaining the two-frequency driving of the liquid-crystal cell 18. Then, a polarizing prism which multiplexes P and S polarized beams passes through the liquid-crystal cell 18 again, converging rod lens 6 and 7 which converge the light mutliplexed by the polarizing prism on two other optical fibers 10 and 11, etc., are provided. |
