Full text loading...
A schematic diagram of the calculated self-self-consistent conduction band profile, quasibound energy levels and wave functions squared for an injector-active region-collector segment of a GaAs∕As QCL for sheet carrier densities of (a) and (b) and an applied external electric field of 60 kV∕cm. The laser levels are shown in bold and the lowest injector state by dashed lines. The doped region of the injector is also indicated.
Simulated field-current density characteristics for a range of doping densities between and at 77 K (arrow represents the increase of the doping level and vertical arrows denote the current saturation). Inset: Measured bias- and optical power-current density characteristics for doping densities of and .
Calculated modal gain as a function of current density for a range of doping densities between and at 77 K in the lasing regime before gain saturation. Dashed lines present linear fits for different doping levels. Horizontal lines indicate how the calculated combined waveguide and mirror losses increase as the doping level is increased (the arrow represents increase of doping level). Inset: Estimated threshold current densities as a function of the doping level. The dashed line represents exponential fit to the data in the noted form.
Simulated saturation current density (circles) and maximal modal gain (squares) as a functions of the doping density. Inset: Experimental measurements of the saturation current in QCLs with 45% (circles) and 33% (diamonds) aluminium mole fraction, respectively.
Article metrics loading...