Effects of well number on temperature characteristics in 1.3-mu m AlGaInAs-InP quantum-well lasers

Effects of well number on temperature characteristics have been investigate d in 1.3-mu m AlGaInAs-InP compressively strained multiple-quantum-well las ers, Well-number dependence of threshold currents (I-th), external quantum efficiencies (eta(d)), characteristic temperatures of I-th and eta(d) and m aximum operation temperatures have been experimentally determined and analy zed, The characteristic temperature of the threshold current (T-0) and the maximum operation temperature (T-max) were found to increase with increasin g the number of quantum wells and a record high pulsed T-max of 220 degrees C has been achieved in lasers with ten wells. In contrast, the characteris tic temperature of the external efficiency (T-eta) was found to decrease wi th increasing the number of wells. Because of this opposite web-number depe ndence of the T-0 and T-eta, each of them alone is not necessarily a good m easure to optimize the number of wells. Therefore, in this work, me also ev aluated a power reduction at a constant current with increasing temperature , which depends on both T-0 and T-eta and thus should be a more practical m easure of the temperature characteristics, and discuss the optimum number o f the quantum wells.