| 摘要 |
PURPOSE:To obtain an optical integrated circuit with high quality by forming two optical waveguide paths in a semiconductor layer at a minute intervals, providing a strip-shaped control electrode on the semiconductor layer between the paths and switching over incident rays to one optical waveguide path according to the intensity of the voltage applied to said electrode. CONSTITUTION:On an N type Si substrate 1, an N<-> type thin layer 2 is formed, and in its center two optical waveguide paths 4 and 5 are bored in parallel to each other at a minute interval. Then, an N type impurity with high concentration is diffused into the layer 2 exposed between these optical waveguide paths 4 and 5 order to form a N<+> type region 9, on which a strip-shaped electrode 7 is attached through a strip-shaped SiO2 film 6. The whole lower surface of the substrate 1 is coated with an electrode 8. Thereby, an MOS structure is formed by the region 9, the film 6 and the electrode 7, and by varying the depth of the depletion layer formed in the region 9, i.e., the degree of coupling, according to the intensity of the voltage applied to the electrode 7, incident rays are switched over between the optical waveguide paths 4 and 5. |
