| 摘要 |
PURPOSE:To lower the degradation in extinction ratio at the time of ultra-high- speed modulation and at the time of high-input optical modulation by using a multiple quantum well layer which is increased in the electric field intensity of quantum wells in an electron transportation direction when an electric field is impressed thereto as the multiple quantum well layer of a light absorption layer. CONSTITUTION:A p type GaAs layer (p type semiconductor layer) 11 is provided on the light absorption layer 20 of the multiple quantum well structure of, for example, 50 number of the quantum wells as the I layer of a pin structure. A p side electrode is provided thereon and further, a circular window for introducing incident light A is provided on a p type GaAs layer 11 and a p side electrode 13. On the other hand, an n type GaAs layer (n type semiconductor layer) 12 is provided under the light absorption layer 20. An n side electrode 14 is provided thereon and further, a circular window 16 for leading out the exit light B is provided on the n type GaAs layer 12 and the n side electrode 14. The light absorption layer 20 which is increased in the electric field intensity of the quantum wells in the electron transportation direction when the electric field is impressed thereto is used as the multiple quantum well layer. |
