The differential efficiency of quantum-well lasers

We have analyzed the internal differential efficiency of quantum-well lasers in terms of current spreading, carrier injection into the well, and the radiative efficiency within the well. We quantify the first two of these processes by extracting information from spontaneous emission measurements as a function of device length, current, and temperature. We show that the carrier injection efficiency is responsible for the temperature dependence of the external differential efficiency of GaInP quantum-well (QW) lasers by comparing values from the slope of the laser power output versus current characteristic with our experimental values for current spreading and injection efficiency.