Temperature profile along the cavity axis of high power quantum well lasers during operation

Measurements of the temperature distribution along the cavity of 0.5 W AlGaAs quantum well lasers are presented. The spatial distribution of temperature was determined by measuring the spectral shift of electroluminescence emitted through a window in the GaAs substrate metallization. The average temperature of the active layer is 10–15 K higher than the heatsink temperature at 0.5 W output. Facet temperatures can exceed the average active layer temperature by over 100 K. Data are also presented illustrating the temperature profile at different drive currents between threshold and the maximum operating current. A temperature profile of a laser with a damaged front facet is presented, showing a hot region that is twice the size of the defect.