It is the most important core for high brightness high power semiconductor lasers to improve the resistance to catastrophic optical damage (COD) and output operation characteristic of broad area laser diodes (LDs). According to the sputter-reaction theory of passivation with nitrogen-hydrogen plasma, and using high thermal heat-conduction AlxNy film to protect the passivated cavity, peak output power has increased by 66.7% for the new device. The aging speed of the LDs is less than 0.73% per 1000 h when they are working under continuum current operation with the output power of 3.5 W.