| 摘要 |
PURPOSE:To improve high-frequency response characteristics by forming an optical waveguide of a semiconductor thin film, and setting the film thickness at a single mode under the waveguide-mode conditions of incident light. CONSTITUTION:On a GaAs semi-insulating substrate 1, the following layers are sequentially laminated. As a buffer layer, a phi-GaAs layer 2 is laminated. As a first clad layer, phi-Al0.5Ga0.5As 3 is laminated. As a waveguide layer 4, a phi-Al0.2Ga0.8As layer is laminated. As a second clad layer, a phi-Al0.5Ga0.5As layer is laminated. Furthermore, an n-GaAs layer wherein Si is doped is laminated thereon as an active layer 6. As a light receiving device, a FET type photodetector is provided. Since the waveguide layer is formed thinly, the signal light is efficiently received into the light receiving device at a high speed because the propagating light is propagated at a single mode. Therefore, the length of the light receiving part can be made shot, the capacity becomes small and the high-frequency response characteristics are improved. |
