| 摘要 |
PURPOSE:Not only to moderate technique difficulties in the etching of an active layer but also to enable a high speed modulation through the junction capacitance of a current block layer by a method wherein the stripe width of the active layer is made large depending on the current blocking layer formed of a high resistance doped crystal layer and a concave reflective mirror. CONSTITUTION:A current block layer 15 of a BH(Buried Hetero) type semiconductor laser is a high resistance doped crystal layer formed of such as Fe coped GaInAsP. As a dopant functions as a trap, the high resistance doped crystal layer is not only high in resistance to display a required current blocking effect but also free from the influence of a junction capacitance to enable a high speed modulation. And, the current block layer 15 formed of the high resistance doped crystal layer makes the stripe width W2 of an active layer 13 large, which can oscillate in a lateral base mode. And, reflective mirrors 17 and 18 are formed to have a concave plane with a large curvature respectively to make the stripe width W2 of the active layer 13 large. The current block layer 15 is slightly lower than the active layer 13 in refractive index, and the refractive index difference between the active layer and the current block layer 15 is made small so as to enable the active layer 13 to be buried. |
