Паразитная рекомбинация в лазере с асимметричными барьерными слоями

In a laser with asymmetric barrier layers (ABLs) two thin barrier layers adjacent to the active region on both sides are aimed at prevention of bipolar population of the waveguide layers and, accordingly, at suppression of parasitic recombination in them. In the present work, a theoretical model of the laser with ABLs based on rate equations is proposed, which includes unwanted carrier leakage that inevitably occurs in lasers with ABLs implemented in practice. Solutions of the equations for the steady-state mode are obtained. Using an example of a laser based on an InGaAs/GaAs quantum well (lasing wavelength λ = 980 nm) the effect of the leakage through ABLs on device characteristics is studied. The parasitic fluxes suppression ratios C of ABLs that are required for prevention of unwanted impact of waveguide recombination are estimated. For the case under consideration the effect of using ABLs becomes pronounced at the suppression ratios C ≥ 102. To suppress 90% of the parasitic current, C should be equal to 2.3 · 10^4. In the work, we also study the influence of ABLs on the useful fluxes of carriers entering the active region.