Semiconductor laser

A semiconductor laser comprising:

• (i) a semiconductor base structure including a GaAs substrate of one conductivity type, provided with an etched channel, a current-blocking layer consistIng of GaAs of an opposite conductivity type and formed on the surface of said substrate, except over said channel, a channel deformation-preventing layer formed of Ga.sub.l-x Al.sub.x As (0.1.ltoreq.x.ltoreq.1) and formed on the surface of said current-blocking layer, said channel deformation-preventing layer having a thickness of 0.2 .mu.m or less, and an oxidation-preventing layer formed of GaAs and formed on the surface of said channel deformation-preventing layer;
• (ii) a laminated semiconductor structure formed on said base structure and including a lower cladding layer formed on the surface of said semiconductor base structured including said channel, an active layer formed on the surface of said lower cladding layer, and an upper cladding layer formed on the surface of said active layer;
• and
• (iii) an electrode means for applying current to said active layer.

A semiconductor laser comprising:

• (i) a semiconductor base structure including a GaAs substrate of one conductivity type provided with an etched channel, a first channel deformation-preventing layer formed of Ga.sub.l-x Al.sub.x As (0.1.ltoreq.x.ltoreq.1) and formed on the surface of said substrate except over said channel, said channel deformation-preventing layer having a thickness of 0.2 .mu.m or less, a current-blocking layer consisting of GaAs of an opposite conductivity type and formed on the surface of said first channel deformation-preventing layer, a second channel deformation-preventing layer formed on the surface of said current-blocking layer, and an oxidation-preventing layer formed of GaAs and formed on the surface of said second channel deform'tion-preventing layer;
• (ii) a laminated semiconductor structure formed on said base structure and including a lower cladding layer formed on the surface of asid semiconductor base structure including said channel, an active layer formed on the surface bf said lower cladding layer, and an upper cladding layer formed on the surface of said active layer;
• and
• (iii) an electrode means for applying current to said active layer.