| abstract |
Laser light having high beam quality with high emission efficiency of laser light, less waveform distortion, and suppressed mode disturbance can be obtained. A semiconductor optical amplifier structure having a stepped ridge structure in which a laser part 25 of a semiconductor laser structure, a tapered InP clad layer 16 and an InGaAs contact layer 17 are stacked in two steps on an InP substrate 11. A layer structure including the light amplification portion 26 is formed. [Selection] Figure 2 |