| 摘要 |
PURPOSE:To provide an inversion DELTAbeta type directional coupler with operating voltage lower than that of a conventional one. CONSTITUTION:This switch is equipped with a substrate 11 provided with an electrostrictive effect, two waveguides 13a, 13b formed on the substrate 11 in parallel, and electrodes 15a-15d for refractive index control that is the electrodes 15a, 15b (15c, 15d) for refractive index control provided by N pieces (2 pieces in this case) on the waveguide and which constitute N pairs of electrodes (two pairs in this case) between the electrodes 15c, 15d (15a, 15b) provided on the other waveguide and the former electrodes. Furthermore, a weak coupling part 21 to weaken coupling between the two waveguides 13a, 13b weaker than coupling at another part of a substrate part equivalent to a part between the pairs of electrodes is provided in a center part observing from the longitudinal direction of respective waveguide at a part equivalent to a part between N pairs of electrodes among the substrate parts between the two waveguides 13a, 13b. |
