| 摘要 |
PURPOSE: To obtain a focal point which varies in an optical axis direction for the purpose of position detection and aligns to a direction perpendicular to the optical axis direction. CONSTITUTION: An optical waveguide 12 is produced in succession to an optical waveguide 11 by a proton exchange method after the production of the optical waveguide 11 by a thermal diffusion method of Ti on an LiNbO3 substrate 1. The crystal bearing of the LiNbO3 substrate 1 is so selected that either of TE or TM light is an extraordinary ray and the other is an ordinary ray. The ordinary ray is propagated in the optical waveguide 11 and is emitted from an end face 21 and the extraordinary ray is emitted from an end face 22 after propagation in the optical waveguides 11, 12 if both of the ordinary ray and the extraordinary ray are propagated. The ordinary ray and extraordinary ray emitted from the end faces 21, 22 respectively focus at the two points 41, 42 different only in the optical axis direction by a condenser lens 30. |
