The output facet temperature of high‐power AlGaAs/GaAs single quantum well (SQW) laser diodes was measured during operation. The front output facets were passivated with Al2O3coatings. The spectral shift of photoluminescence from the cladding layers was used to determine the temperature rise at the front facet with increasing output power. The spatial resolution of the technique allowed to look at each cladding layer individually and to study the correlation between the near‐field pattern and the temperature profile along the active layer. The local temperature on the facet at 1 W total optical power (corresponding to an average linear power density of 10 mW/&mgr;m) was found to vary between 25 and 45 K above the average active layer temperature and to exceed the heat‐sink temperature by up to 70 K. This represents a significant reduction of facet temperature in comparison to earlier reports and can be attributed to high‐quality passivation coatings. ©1996 American Institute of Physics.