A semiconductor laser with a window structure which can emit a light beam with
a non-deviated outgoing angle. The semiconductor laser emits a light beam generated
at an active layer via a window section. The window section includes a first semiconductor
layer having a first carrier concentration and a second semiconductor layer on
the first semiconductor layer as an extension of the active layer and which has
a second carrier concentration lower than the first carrier concentration. The
window section further includes a third semiconductor layer having a third carrier
concentration. According to the third layer, a refractive index distribution of
the light beam at the window section is symmetrical in the laminating direction,
with the extension of the active layer as a center. Because the beam is uniformly
propagated, the beam can be emitted without being deviated in the laminating direction.