| 摘要 |
PURPOSE:To realize a low loss and to reduce a crosstalk by bringing a liquid crystal to a molecular orientation in the direction of a bisector of a cross angle made by two waveguides, and setting a refractive index of the liquid crystal at the time when an electric field is impressed and when it is not impressed between electrodes, to a value being equal to a refractive index of the waveguide. CONSTITUTION:A liquid crystal cell 1s is field with a liquid crystal, and this liquid crystal has an anisotropy in its refractive index, but brought to a molecular orientation so that the refractive index becomes equal against input use and output use waveguides 10a2, 11a2. That is to say, an empty cell 12 for inserting the liquid crystal has an oriented layer which has been formed on the upper face of a substrate, and this oriented layer is brought to rubbing in the direction of a bisector of a cross angle made by two waveguides 10a2, 11a2, and the liquid crystal is brought to a molecular orientation in the direction in which the rubbing has been executed. Also, a refractive index of the waveguides 10a2, 11a2 is set so as to become roughly equal to a refractive index of the liquid crystal in case when an electric field is not impressed between the upper and lower electrodes of the liquid crystal cell 12. In this way, at the time of a switching operation, a large deflection angle is obtained, a crosstalk is reduced and an insertion loss becomes small. |
