| 摘要 |
PURPOSE:To form an optical logical circuit which includes an optical OR circuit on the same substrate by connecting at least two photoelectromotive force elements in parallel between a couple of electrodes provided to the demultiplexed light waveguide part of a Mach-Zehnder optical waveguide, and applying their terminal voltage. CONSTITUTION:Reference light IinR is guided to the Mach-Zehnder optical waveguide 50 and made to propagate to branch optical waveguide parts 51 and 52 at the same phase speed. The parts 5 1 and 52 are made different in length and the phases when both light beams are multiplexed at a conflux point are made opposite to eliminate light power. A voltage developed by the photoelectromotive force element 21 or 22 is applied between electrodes 30 to vary the refractive index of the part 51 applied with an electric field, thereby varying the phase speed of the light. Namely, when neither of input light signals IinA and IinB is present, the logical value of the output light Iout from an optical waveguide 50 for output is zero. When, however, there is an input light signal to either one, a voltage is applied between the electrodes 30, so the logical value is 1. |
