| 摘要 |
PROBLEM TO BE SOLVED: To improve the temperature characteristics of a wavelength selective optical attenuator used for optical wavelength multiplex communication and the like. SOLUTION: Wavelength multiplexed light is separated for every wavelength by a diffraction grating 15, and a liquid crystal plate 20 is irradiated with the light via aλ/2 wavelength plate 18 and a polarizer 19. The liquid crystal plate 20 transmits the light by rotating the polarization direction by the optical rotatory power of the liquid crystal in an off state where voltage is not applied to each electrode. Also, the liquid crystal plate 20 transmits the light as it is by aligning the liquid crystal molecules in an electric field direction in an on state where the voltage is applied to each electrode of the liquid crystal plate. In this case, temperature dependence disappears and therefore, the wavelength selective optical attenuator reduced in temperature dependence together with the blocking and transmission of the light can be provided. COPYRIGHT: (C)2009,JPO&INPIT
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