An interesting approach is proposed for investigating the thermal stress of AlGaAs/GaAs laser diode bars using infrared thermography.We obtained horizontal and perpendicular profiles of the working thermal stress through the active region in one emitter (emitter 5) at operating currents 0.5 and 1.0 A. The thermal stress at the center of emitter 5 is found to quickly rise to values 2.1 and 3.4 …