Semiconductor optical device and method of manufacturing the same

A semiconductor optical device, comprising:

• a GaAs semiconductor substrate;
• an optical waveguide part including at least one optical element having an optical waveguide, the optical waveguide having a core semiconductor layer and first and second clad semiconductor layers, the core semiconductor layer including at least one of a GaInNAs semiconductor and a GaAs semiconductor and provided on the GaAs semiconductor substrate, the first and second clad semiconductor layers respectively provided on the GaAs semiconductor substrate with the core semiconductor layer therebetween;
• and
• an optical amplification part including at least one semiconductor optical amplifier having an active layer and first and second conductive-type clad layers, the active layer including a GaxIn1−xNyAs1−y semiconductor and provided on the GaAs semiconductor substrate with the active layer adjacent to the core semiconductor layer, the first and second conductive-type clad layers respectively provided on the GaAs semiconductor substrate with the active layer therebetween,
• wherein the optical waveguide part and the optical amplification part are separate and optically connected with each other and integrated on the GaAs semiconductor substrate.