We have measured the temperature dependence of the threshold current of an InGaAsP injection laser pumped by 130‐ps electrical pulses. By comparing the data with the empirical ruleIth=I0 exp(T/T0), we have observed aT0of 148 K. The results indicate that we can partially separate carrier depletion processes, e.g., spontaneous radiative, Auger, or other nonradiative recombination, and carrier leakage from the fast stimulated emission process, hence, eliminate their effect on the temperature stability of the threshold current.