| 摘要 |
A semiconductor laser having a ridge waveguide structure includes: a semiconductor substrate (11); a lower-part clad layer (12) formed on the semiconductor substrate (11); an active layer (13) and a semiconductor layer (16) joined together in parallel on the lower-part clad layer (12); a first upper-part clad layer localized so as to be matched in position to the active layer (13) above the active layer (13) only; a second upper-part clad layer (18) localized so as to be matched in position to the semiconductor layer (16) only above the semiconductor layer (16); and a projecting third upper-part clad layer (18a) formed higher than the active layer (13) and trapping light guided through the active layer (13), the semiconductor layer (16) having a larger band gap than the active layer (13). Using this configuration, a highly reliable optical semiconductor device can be achieved in which electrical crosstalk between lasers and current diffusion in the ridge waveguide structure is suppressed, even when adopting a ridge waveguide structure that is comparatively easily produced. |
