Semiconductor laser device

A semiconductor laser of an SCH structure, comprising:

• an active layer;
• and
• clad layers respectively disposed at both sides of said active layer through confinement layers each having a greater band gap than said active layer, wherein
• said clad layers include a pair of first clad layers each having a greater band gap than said each confinement layer and thickness of 0.003 to 0.3 .mu.m, and
• a pair of second clad layers each having lower refractive index than said each confinement layer, and wherein
• said pair of first clad layers are disposed nearer to said confinement layers than said pair of second clad layers.

A semiconductor laser device, comprising:

• an active layer;
• and
• clad layers respectively disposed at both sides of said active layer, wherein
• said clad layers include a pair of first clad layers, and a pair of second clad layers, said pair of first clad layers being disposed nearer to said active layer than said pair of second clad layers,
• said pair of first clad layers have a greater band gap than said second clad layers and have g thickness small enough to suppress defects according to crystal dislocation, and
• said pair of second clad layers have a lower refractive index than said active layer and a greater band gap than said active layer.

A semiconductor laser device, comprising:

• an active layer;
• clad layers respectively disposed at both sides of said active layer, and
• confinement layers disposed between said clad layers and said active layer, wherein
• said clad layers include a pair of first clad layers, and a pair of second clad layers, said pair of first clad layers being disposed nearer to said active layer than said pair of second clad layers,
• said pair of first clad layers have a greater band gap than said second clad layers and have g thickness small enough to suppress defects according to crystal dislocation, and
• said pair of second clad layers have a lower refractive index than said confinement layers and a greater band gap than said confinement layers.

A semiconductor laser device, comprising:

• an active layer;
• and
• a pair of clad layers respectively disposed at opposite sides of said active layer, wherein
• each of said clad layers includes:
• a first clad layer having a greater band gap than said active layer, and
• a second clad layer having a lower refractive index than said active layer, and wherein
• said first clad layers are disposed nearer to said active layer than said second clad layers.

A semiconductor laser device, comprising:

• an active layer;
• clad layers respectively disposed at both sides of said active layer, wherein
• said clad layers comprise:
• a pair of first clad layers each having a greater band gap than said active layer and having a thickness of not more than 0.3 .mu.m, and
• a pair of second clad layers each having a lower refractive index than said active layer, and wherein
• said pair of first clad layers are disposed nearer to said active layer than said pair of second clad layers.