| 摘要 |
PURPOSE:To realize an integrated optical semiconductor element suitable for using in a coherent optical communication system by restricting reflection of incident light in the interface between a simple substance of light waveguide routes and a light absorbing area, and also preventing the concentrative occurrence of electron/hole pairs on the incident side in the light absorbing area. CONSTITUTION:In an integrated optical semiconductor device where InGaAsP light waveguide routes 23 and Inlays light absorbing layers 14 to absorb light in these light waveguide routes 23 are integrated together, the device has characteristics that the thickness of the light absorbing layers 14 is formed so as to be thin on the rear side and thick on the front side against the light progressing direction in the light waveguide routes 23, and that effective absorbing coefficient against the light waveguide routes 23 in the light absorbing layers 14 is made gradually large along the light progressing direction in the light waveguide routes 23. |
