What Causes the Pulse Power Saturation of GaAs-Based Broad-Area Lasers?

With short current pulses, the output power of semiconductor lasers is limited by non-thermal internal loss mechanisms. Two-photon absorption (TPA) was recently proposed as dominating photon loss process. We investigate this claim by advanced numerical laser simulation that includes all relevant mechanisms self-consistently. Using common material parameters, we obtain good agreement with the measured performance up to 90-W output power. Carrier leakage and free-carrier absorption are identified as the main saturation mechanisms, followed by longitudinal spatial hole burning. Contrary to earlier studies, TPA and gain compression are found negligible.