| 摘要 |
A semiconductor laser device is formed of a semiconductor material assembly including a first semiconductor layer having an active region formed directly by crystal growth on a substrate for the crystal growth having on the surface thereof a second semiconductor layer. A third semiconductor layer is also formed on the first layer. The refractive index of each of the second semiconductor material region and the third semiconductor layer is smaller than that of the first semiconductor layer while the band gap of each of the second semiconductor material region and the third semiconductor layer is broader than that of the first semiconductor layer. In order to provide mode stabilization even at long wavelength, the thickness of the active region formed at the interface between said first semiconductor layer and said substrate for crystal growth is made larger than the thickness of the other portions in the first semiconductor layer so that the effective refractive index to laser beams is changed stepwise in a direction perpendicular to the direction of the laser beams. |
