| 摘要 |
PURPOSE:To make the controlling of the transmission characteristics of the optical fiber by equally dividing incident light to two lines by a 3dB optical branching filter, changing the optical path length by way of a light variable phase shifter or changing the refractive index by electro-optic effect, magneto-optic effect, acousto- optic effect or the like and combining the light by a photocoupler. CONSTITUTION:A pattern such as the one shown in the figure is formed by photolithographic techniques on LiNbO3 crystal 4 or the like. The portions 5-7 where Ti is diffused are high in refractive index and form a core layer. Thereby, the 3dB branching filter and photocoupler are formed. Electrodes 8, 9 are formed on one or both of the two central core layers 6, 7 to permit application of voltage, whereby the light variable phase shifter is constituted. As voltage is applied to the electrodes 8, 9, the refractive index changes and the transmission characteristics of the filter changes. Hence, the transmission characteristics of the filter may be controlled. |
