Quantum design of a 1.3 μm InGaPAs semiconductor laser
Semiconductor wafer growth can now produce heterostructures of very high quality with stoichiometrically correct growth of individual monolayers. Despite significant advances in MBE and MOCVD growth technologies, a critical void has remained in predicting the performance of final packaged functional amplifier or laser devices. The lack of predictive semiconductor device design and growth monitoring capability can be traced to the extreme complexity of calculating the semiconductor optical response and radiative-nonradiative recombination rates from first principles. Considering the critical role of the above recombination processes in not only, determining gain and slope efficiency but, also all dynamic properties (modulation rates, gain switching, injection locking etc) of SOAs and SLs, it is clear that the impact of this work reaches well beyond the accurate prediction of an L-I characteristic.
Closed-loop design of a semiconductor laser
We present an overview of a novel first principles quantum approach to designing and optimizing semiconductor QW material systems for target wavelengths. Using these microscopic inputs as basic building blocks we predict the L-I characteristic for a low power InGaPAs ridge laser without having to use adjustable fit parameters. Finally we employ these microscopic inputs to develop sophisticated simulation capabilities for designing and optimizing end packaged high power laser structures. As an explicit example of the latter, we consider the design and experimental demonstration of a vertical external cavity semiconductor laser (VECSEL).
Beyond the ABC: carrier recombination in semiconductor lasers
It is demonstrated that fully microscopic many-body models are required for a correct description of the dominant carrier loss processes in semiconductor lasers, spontaneous emission and Auger recombination, and that they are able to quantitatively predict these losses. The density dependence of the losses assumed in semi-empirical approaches, J=AN+BN2+CN3, is shown to break down already near transparency. For the spontaneous emission it is shown to decrease from quadratic to linear (BN), Auger rates are shown to increase only quadratically (CN2) or even less.