| 摘要 |
PURPOSE:To modulate the intensity of the guided light propagating in waveguides by injecting carrier layers into the intersected part of a main waveguide layer which consists of a multiple quantum well structure and is sandwiched by a specified emitter layer and collector layer, thereby changing the refractive index. CONSTITUTION:Multilayered semiconductor layers constituting a light guide layer 1 intersected to an X shape are provided on an n-GaAs substrate 7. A transistor is constituted of the multiple quantum well 1, an n-AlxGa1-xAs emitter layer constituted of the clad layer 2, a base region consisting of the multiple quantum well and a collector layer 8. The conduction band bottom of the emitter layer is set at the value equal to or slightly smaller than n=1 quantum level formed in the multiple quantum well layer 10. The conductor bottom of the emitter layer shifts to the energy position larger than the n=1 quantum level when a bias voltage is impressed between the base and emitter in such a manner. The high-speed modulation to the guided light from a light incident port 3 is thus executed. |
