The facet heating behavior of AlGaAs double-heterojunction (DH) lasers was measured as a function of injection current using Raman microprobe spectroscopy. The result from the DH lasers is compared to AlGaAs ridge-waveguided single quantum-well (SQW) lasers. A clear discontinuity in the facet temperature rise was found below and above the lasing threshold for the DH lasers, indicating a substantial contribution to facet heating by the photon flux. This is in contrast to the facet heating behavior of SQW lasers in which photon flux has been shown to play only a minor role. The data suggest a large difference in the facet absorption of the lasing photons between the two types of lasers. This is further supported by the effect of argon laser probe beam induced facet heating on the diode laser's output power.