| 摘要 |
A semiconductor laser includes a semiconductor substrate of a first conductivity type and having a front surface; a first semiconductor layer disposed on the front surface of the semiconductor substrate and having a refractive index that increases with distance from the semiconductor substrate; an active layer disposed on the first semiconductor layer; and a second semiconductor layer disposed on the active layer, having a refractive index that decreases with distance from the active layer, and having a ridge. In this laser, the refractive index distribution between the ridge and the substrate is asymmetrical about the active layer so that the center of the light intensity distribution shifts from the active layer toward the substrate, in the direction perpendicular to the front surface of the substrate. Therefore, propagated light is hardly affected by the refractive index distribution in the width direction of the laser, which is caused by the presence of the ridge, whereby occurrence of a higher mode is suppressed.
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