| 摘要 |
PURPOSE:To flatten a chirping characteristic by forming the far and near end faces of an active region from a photowaveguide and the far end face of the photowaveguide from the active region in resonator surfaces. CONSTITUTION:An N-type InGaAsP photowaveguide layer 2 is formed on an N-type InP substrate 1. An active region 8 is formed of an N-type InP separating layer 3 on the layer 2, an N-type InGaAsP active layer 4, a P-type InP closing layer 5 and electrodes 6, 7. A photowaveguide 9 is formed of the portions except the region 8 of the layers 2, 3. A semiconductor laser 13 is formed by resonator surfaces 10, 11, 12, a light emitted from the surface 10 is guided to a polarized wave plane preserving fiber 14 to construct a signal source for a coherent light communication. The laser light propagated through the fiber 14 is mixed through a local oscillation laser light 17 and a light coupler 16 by a detector 15. With this construction, chirping characteristic for a modulating frequency can be flattened. |
