| 摘要 |
PURPOSE:To make the integration easy by a method wherein a waveguide is formed collectively at a light detector and the light is made easily incident so that the efficiency to couple with an optical fiber can be enhanced and that the light can be made incident from a cleavage face. CONSTITUTION:A compound semiconductor light-absorption layer whose conductivity type is an i-type or a type close to the i-type, e.g., an n-type GaAs light-absorption layer 12B, is constituted in such a way that it is sandwiched between a p-type compound semiconductor light waveguide layer, e.g., a p-type AlGaAs light waveguide layer 12A, and an n-type compound semiconductor light waveguide layer, e.g., an n-type AlGaAs light waveguide layer 12C. If the light L is incident in a state that a reverse bias voltage from a power supply E is impressed between a region 14 and a region 15, an electron and hole pair is generated in the light-absorption layer 12B. In the light waveguide layer 12A or 12C, the light which is incident from an oblique direction advances while it is reflected between the light waveguide layer 12A and the light-absorption layer 12B and generates the electron and hole pair when it enters the light-absorption layer 12B. From the electron and hole pair generated in this manner, an electron proceeds to the p-type impurity diffusion region 14 via the light waveguide layer 12A; a hole proceeds to the n-type impurity diffusion region 15 via the light waveguide layer 12C; the light is then detected.
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