Optical semiconductor device

摘要

In an optical semiconductor device including a DFB laser and a light absorption modulator, a semi-insulating semiconductor layer is disposed between a carrier blocking layer and a upper cladding layer, the upper cladding layer having an opposite conductivity type from that of the semiconductor substrate and disposed on a buried waveguide and the carrier blocking layer. The capacitance between the carrier blocking layer and the upper cladding layer is reduced. Therefore, mutual interference between the DFB laser and the light absorption modulator through the carrier blocking layer is reduced.