ON NONUNIFORM PUMPING FOR MULTIPLE-QUANTUM-WELL SEMICONDUCTOR-LASERS

Optical gain distribution among quantum wells for (strained) multiple- quantum well (MQW) lasers was analyzed to understand the effect of non uniform pumping. The nonuniform gain distribution is mainly caused by stagnant hole transport across the quantum wells. Contrary to what peo ple expected, neither uniformly p-doped MQWs nor selectively p-doped M QWs can alleviate the nonuniform pumping problem. The most effective s olution is employing an exponential p-doping profile which can counter balance the nonuniform injection effect. Our simulation results showed that such an exponential p-doping profile has a characteristic length around one-half of the ambipolar diffusion length. (C) 1994 American Institute of Physics.