Three Dimensional Thermal Problems of Double-Heterostructure Semiconductor Lasers

Numerical analyses of the three dimensional thermal problem of double-heterostructure lasers were carried out. In particular, a multi-layered structure composed of nonuniform materials was treated, and the local heating arising at the tiny solder voids was investigated in detail. The allowable void size at which the local heating is suppressed below 10% of the uniform temperature rise was determined to be less than 4 µm × 4 µm. The complicated temperature distribution on the mirror facet obtained numerically was compared with the experimental result, showing good agreement. The observed nonuniform temperature distribution along the stripe was correlated with the lasing characteristics, e.g., a large threshold current increase at cw operation and the rapid degradation.