Improved 808-nm High-Power Laser Performance With Single-Mode Operation (Vertical Direction) in Large Optical Cavity Waveguide

We present a detailed study of the effect of large optical cavity (LOC) waveguide design on the laser's kink performance and it was found that a multimode waveguide in the epi growth direction could lead to the occurrence of the power kink in the light-current (L-I) curve, and the occurrence of the power kink was accompanied with the broadening of the beam divergence in the wafer growth direction. In order to eliminate the kink issue that is associated with the lasing of the higher-order modes, a new type of waveguide, which is called higher-order-mode tunneling waveguide, was proposed in our design. The new type of waveguide can strongly promote the leakage of higher-order modes, and in this way, the LOC waveguide becomes single-moded. Test of the fabricated devices based on the new design showed that the devices indeed exhibited perfect L-I linearity without kinks.