Vertical cavity surface emitting laser diode (vcsel) with multiple current confinement layers

A vertical cavity surface emitting laser diode (VCSEL), comprising:

• a multi-layer structure on a substrate, wherein the multi-layer structure comprises:
• an active region, comprising three or more active layers, wherein a tunnel junction is provided between every two adjacent ones of the active layers;
• and
• a plurality of current confinement layers, at least comprising a first current confinement layer, a second current confinement layer and a third current confinement layer, wherein, the first current confinement layer at least has a first optical aperture (OA), the second current confinement layer at least has a second OA, the third current confinement layer at least has a third OA, the first OA, the second OA and the third OA are uninsulated portions of each of the plurality of current confinement layers, wherein one of the first OA, the second OA and the third OA is disposed outside the active region, and another of the first OA, the second OA and the third OA is disposed inside the active region, and the other of the first OA, the second OA and the third OA is disposed inside or outside the active region, the tunnel junction is positioned between the first OA and the second OA or between the second OA and the third OA.