Tunnel regenerated coupled multi-active-region large optical cavity laser with high quality beam

A novel coupled multi-active-region large optical cavity structure cascaded by tunnel junction is proposed to solve the problems of catastrophic optical damage (COD) of facet and large vertical divergence caused by the thin emitting area in the conventional laser diode. For the 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 structure parameters, the beam quality is greatly improved, and the level of COD power increases more than two times compared with that of the conventional laser.