Multi-Junction, Polarization-Controlled Vertical Cavity Surface Emitting Laser and Method of Fabrication Thereof

A method of fabricating a vertical cavity surface emitting laser (VCSEL) comprising:

• (a) forming or providing a first semiconductor wafer comprising, from a bottom to a top thereof, a first semiconductor substrate and a bottom distributed Bragg reflector (DBR);
• (b) forming or providing a second semiconductor wafer comprising, from a bottom to a top thereof, a second semiconductor substrate and a semiconductor active region comprising at least one active subregion and a top cavity layer on a side of the at least one active subregion opposite the second semiconductor substrate, wherein each active subregion comprises:
• a pair of cavity layers separated by a tunnel junction layer and a quantum well layer on a side of the pair of cavity layers opposite the second semiconductor substrate, or
• a pair of cavity layers separated by a quantum well layer and a tunnel junction layer on a side of the pair of cavity layers opposite the second semiconductor substrate;
• (c) coupling the bottom DBR and the semiconductor active region with the second semiconductor substrate disposed on a side of the semiconductor active region opposite the bottom DBR and then removing the second semiconductor substrate;
• (d) following the removal of the second semiconductor substrate, forming on a side of the semiconductor active region opposite the bottom DBR a top DBR;
• and
• (e) forming on all or part of the at least one active subregion of the semiconductor active region a current confinement structure.