Constricted double‐heterojunction diode lasers of positive‐index lateral guiding and low‐threshold‐current design are found to operate cw to 170 °C (ambient temperature) and pulsed to 280 °C. High threshold‐current temperature coefficients (T0≳230 °C) and constant differential quantum efficiencies are found up to 100 °C. Above 100 °C the temperature‐dependent current‐focusing effect responsible for high‐T0behavior appears to saturate. Single‐longitudinal‐mode cw operation is recorded up to 150 °C. Two effects, a strong temperature dependence of the threshold current density above 180 °C (T′0= 40–50 °C), and sublinear spontaneous emission above 220 °C, are believed to reflect the same nonradiative Auger recombination process currently proposed to explain InGaAsP laser behavior near room temperature.