US 5,345,461 A · Semiconductor laser high optical gain quantum well

Abstract

A semiconductor laser including an n-type GaAs substrate, an n-type clad layer formed over the substrate, an undoped AlGaAs active layer formed over the clad layer, the active layer having a varying aluminum content depending on the level therein, to form predetermined asymmetric quantum wells, a p-type clad layer formed over the active layer, and a p-type cap layer formed over the p-type clad layer. The active layer has a lower surface constituted by Al.sub.y Ga.sub.1-y As having a low aluminum content and an upper surface constituted by Al.sub.z Ga.sub.1-z As having a high aluminum content, and the aluminum content of the AlGaAs of the active layer present between the lower and upper surfaces increases gradually, while the AlGaAs of both types of the clad layers includes Al.sub.x Ga.sub.1-x As having an aluminum content higher than that of the active layer, to form an asymmetric graded quantum well structure. The AlGaAs of the active layer includes Al.sub.y Ga.sub.1-y As having a low aluminum content, while the AlGaAs of both types of the clad layers includes Al.sub.x Ga.sub.1-x As having a high aluminum content, to form an asymmetric stepped quantum well structure.

Claims18

Dependent claims

A semiconductor laser comprising:

a first compound semiconductor layer of a first conductivity type as a substrate;
a second compound semiconductor layer of the first conductivity type as a first clad layer disposed over the first compound semiconductor layer;
a third compound semiconductor layer of a non-conductive type as an active layer disposed over the second compound semiconductor layer, the third compound semiconductor layer having asymmetric quantum wells;
a fourth compound semiconductor layer of a second conductivity type as a second clad layer disposed over the third compound semiconductor layer;
and
a fifth compound semiconductor layer of the second conductivity type as a cap layer disposed over the fourth compound semiconductor layer.

3 more elements

A semiconductor laser comprising:

a first compound semiconductor layer of a first conductivity type as a substrate;
a second compound semiconductor layer of the first conductivity type as a first clad layer disposed over the first compound semiconductor layer;
a third compound semiconductor layer of a non-conductive type quantum well, as an active layer, disposed over the second compound semiconductor layer, the active layer having a gradual change in composition between an upper surface and a lower surface of the active layer;
a fourth compound semiconductor layer of a second conductivity type as a second clad layer disposed over the third compound semiconductor layer;
and
a fifth compound semiconductor layer of the second conductivity type as a cap layer disposed over the fourth compound semiconductor layer.

3 more elements

Dependencies are inferred from the claim text.

Semiconductor laser high optical gain quantum well

Life of this patent

Semiconductor laser high optical gain quantum well

Life of this patent

Abstract

Claims18