Optimisation of doping cladding layers in AlGaInP/GaInP laser heterostructures

The influence of cladding doping level on the characteristics of laser diodes, which are based on an AlGaInP/GaInP/GaAs system and emit at wavelengths of 670–680 nm, is studied. It is shown experimentally that, as the ratio of the cladding doping levels P/N increases, the inversion current density J₀ and the differential gain β also increase. A monotonic increase in the characteristic temperature T₀ accompanies this process. The internal quantum yield η₀ of stimulated recombination has a maximum at P/N = 2.1. Laser diodes with a mesastripe width of 100 μm are manufactured. The cw radiation power emitted by them is as high as 1000 mW at an efficiency of 1.55 W A^-1.