| 摘要 |
PURPOSE:To make the title device smaller and to increase a manufacturing yield by mutually approaching two light wave guides in a coupling part, forming them in parallel, and arranging a metal so as to cover the light wave guide in the coupling part. CONSTITUTION:An electrode 7 of the title light directionality coupler is provided in the coupling part of a light wave guide 6 so as to sandwich the light wave guide, and generates electrolysis in a Z direction for the light wave guide 6. By impressing the electric field in the Z direction, since a maximum electrochemical constant can be obtained, a switching voltage can be made lower. Light made incident from the light wave guide is propagated in the light wave guide as a TE wave and a TM wave, a separate polarizer is conventionally provided in order to cut or attenuate the TM wave, whereas, in such a case, since the arrangement of a metal such as Al is sufficient, the coupler is effective for the decrease of insertion loss for an optical pulse tester and the miniaturization of the tester. |
