| 摘要 |
PURPOSE:To rotate a plane of polarization of incident light by a specified angle by forming an optical waveguide having a direction of guided wave arranged in the direction of Z axis of a crystal in an LiNbO3 substrate, and providing an electrode so as to impress an electric field to the optical waveguide along a direction of Y axis. CONSTITUTION:An optical waveguide is formed by arranging a longer edge parallelly to a crystal axis Z and a shorter edge parallelly to a crystal axis Y, in an LiNbO3 substrate 10. An optical waveguide 11 is formed by the diffusion of Ti from the surface in the substrate 10, and an optical axis of the waveguide 11 is aligned to the direction of Z axis of the substrate crystal. A pair of travelling wave type electrode 12A, 12B are provided on the substrate interposing the waveguide 11. When an electric voltage is impressed across the electrode 12A, 12B, an electric field 13 is impressed in Y axis direction intersecting the waveguide 11. When incident light 14 having a plane of polarization at 45 deg. to the Y axis is inputted from an incident end of the waveguide 11, the plane of polarization causes rotation by the electro-optical effect, and output light 15 forms a plane of polarization rotated by -45 deg. to the Y axis, namely, by 90 deg. to the incident light. |
