A tunnel regenerated coupled multi-active-region large optical cavity laser with a high quality beam

A novel coupled multi-active-region large optical cavity structure cascaded by a tunnel junction is proposed to solve the problems of facet catastrophic optical damage (COD) and the large vertical divergence caused by the thin emitting area in conventional laser diodes. For a laser with three active regions, a slope efficiency as high as 1.49 W/A, a vertical divergence angle of 17.4°, and a threshold current density of 271 A/cm2 are achieved. By optimizing the structural parameters, the beam quality is greatly improved, and the level of the COD power increases by more than two times compared with that of the conventional laser