Electron affinity engineered VCSELs

A VCSEL system comprising:

• a first mirror;
• and wherein:
• the first mirror comprises a plurality of pairs of layers;
• each pair of layers of the plurality of pairs has a first layer and a second layer;
• the first layer comprises AxB1−xC;
• the second layer comprises AyB1−yC;
• x+y=1;
• a transition layer is situated between each first layer and each second layer;
• the transition layer, in a direction of a first layer to a second layer, has a ramp change in content of A from x=a first value of x to a second value of x=P, wherein P is less than 0.4, and a step change in content of A from x=P to y;
• the transition layer in a direction of a second layer to a first layer, has a step change in content of A from y to y=P and a ramp change from P to the first value of x.

A VCSEL system comprising:

• a first mirror;
• and wherein:
• the first mirror comprises a plurality of pairs of layers;
• each pair of layers has a first layer and a second layer;
• the first layer comprises AxC;
• the second layer comprises AyC;
• x+y=1;
• a transition layer is situated between each first layer and a second layer;
• the transition layer, in a direction of a first layer to a second layer, has a first change from x to P, and a second change from P to y, wherein P≦0.4 for the direction of a first layer to a second layer:
• the transition layer in a direction of a second layer to a first layer, has a third change from y to P, and fourth change from P to x;
• and P≦1 for the direction of a second layer to the first layer.

A VCSEL system comprising:

• a substrate;
• a first mirror stack situated on the substrate;
• an active region situated on the first mirror stack;
• a second mirror stack situated on the active region;
• wherein:
• the first mirror stack comprises a plurality of pairs of AlxGa1−xAs and AlyGa1−yAs layers;
• an interface between each AlxGa1−xAs layer and AlyGa1−yAs layer;
• the interface comprises:
• at least one linear ramp change of Al composition from x=first value to x≦a second value, the second value less than 0.4;
• and at least one step change of Al composition from the second value to a third value.

A VCSEL system comprising:

• a substrate;
• a first mirror stack formed over the substrate, the first mirror having pairs of layers, each pair having a first layer and a second layer;
• an active region including a plurality of quantum wells formed over the first mirror stack;
• a second mirror stack formed over the active region, the second mirror stack having pairs of layers, each pair including a third layer and a fourth layer;
• a first spacer layer between the active region and the first mirror stack and a second spacer layer between the active region and the second mirror stack;
• and
• an interface formed between the first layer and second layer of each pair in the first mirror stack, the interface comprising:
• a first portion where a composition of a first element ramps from a first value to a second value, and a step in the composition from the second value to a third value, the second value selected such that electron affinity on a first side of the step is substantially the same as an electron affinity on a second side of the step.