| 摘要 |
PURPOSE:To improve a receiving sensitivity by integrating a light amplifier monolithically. CONSTITUTION:Because a gate electrode 15 is a Schottky electrode, a depletion layer extends into an active layer 12. The width of this depletion layer changes by a gate voltage and a channel width changes accordingly. As a result, electric current flowing between drain electrode 14 and source electrode 13 changes. When the depletion layer reaches a buffer layer 11, a channel is closed and electric current does not flow. When the light of a semiconductor laser is injected into a light amplifier in this state, the light is amplified by the light amplifier, once comes out of the space of a groove 18, and is thereafter injected into a photodetector and absorbed by the active layer 12 so that a carrier is generated there. As a result, the potential in the vicinity of the channel changes and electric current flows between source 13 and drain 14. Thus, the light amplifier is formed before the photodetector so that the minimum receiving sensitivity is improved in comparison with the case of using only the photodetector. |
