Design of a new asymmetric waveguide in InPBased multiquantum well laser

Today, electron leakage in InPbased separate confinement laser diode has a serious effect on device performance. Control of electron leakage current is the aim of many studies in semiconductor laser industry. In this study, for the first time, a new asymmetric waveguide structure with ninterlayer for a 1.325 μm InPbased laser diode with InGaAsP multiquantum well is proposed and theoretically analyzed using the PICS3D simulation software. The simulator selfconsistently combines the 3D simulation of carrier transport, selfheating, and optical waveguiding. Through the simulation, the optical and electrical performances of laser diodes with symmetric and asymmetric waveguides are studied. Numerical simulation reveals that the asymmetric structure exhibits higher output light power, slope efficiency, emission intensity, and series resistance, as well as lower electron leakage and threshold current density under identical conditions, compared with the symmetric structure. The performances are greatly enhanced in the laser diode with asymmetric waveguide design because of the improved radiative stimulated recombination rate, declined nonradiative Auger recombination rate and decreased overlap between the optical wave and the pdoped layer.