Comparison of the facet heating behavior between AlGaAs single quantum well lasers and double-heterojunction lasers

Abstract

The facet heating behavior of AlGaAs ridge-waveguided single quantum well (SQW) lasers and double-heterojunction (DH) lasers was measured using Raman microprobe spectroscopy. For the SQW lasers, samples with various ridge widths and cavity lengths were measured as a function of output power and injection current. The facet temperature was found to scale with the injection current density rather than the photon flux. In addition, no large discontinuities were found below and above the lasing threshold suggesting that the absorption of the emitted photons plays only a minor role in the initial stage of SQW facet heating. In contrast, 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. 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.