| 摘要 |
PURPOSE:To control the propagating state of light by the intensity or wavelength of incident light by constituting optical waveguide parts of >=2 kinds of materials having different forbidden band widths. CONSTITUTION:The two optical waveguides 9 are formed on a GaxAl1-xAs clad layer 8 on a GaAs substrate 7, i.e., one optical waveguide is formed of a Gay Al1-yAs layer 10 and the other optical waveguide is formed of a GayAl1-yAs layer 11 and a GazAl1-zAs layer 12. The thicknesses of the layers 8, 10-12 are respectively 2, 1.5, 1 and 0.5mum. The width of the optical waveguides A, B is made 2mum and the spacing therebetween is made 3mum. The incident light is absorbed by the layer 12 according to the intensity of the light input and the number of the generated carriers changes when the light having photo energy larger than the forbidden band width of the layer 12 is made incident on the optical waveguide part A. The propagation constant of the optical waveguide is thereby changed and therefore the coupling state of the two optical waveguides A, B changes and the intensities of the light outputs at the exit ends of the two waveguides A, B behave respectively as shown by the curves in the figure. |
