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 nonuniform pumping. The nonuniform gain distribution is mainly caused by stagnant hole transport across the quantum wells. Contrary to what people expected, neither uniformly p-doped MQWs nor selectively p-doped MQWs can alleviate the nonuniform pumping problem. The most effective solution is employing an exponential p-doping profile which can counterbalance 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.