Dependence of Threshold Current on QW Position and on Pressure in 1.5 ?m InGaAs(P) Lasers

The threshold current has been measured as a function of pressure for a series of 1.5 μm InGaAs(P) lasers in which the position of the quantum wells (QWs) has been varied within the active region. Devices with the QWs positioned towards the p-doped cladding layer exhibit both a lower threshold current density and a reduced pressure dependence of the threshold current compared to devices with the QWs placed either symmetrically between the cladding layers or towards the n-doped cladding layer. Monte-Carlo simulations of the trajectories of Auger-generated hot carriers show that the escape probability of hot holes depends considerably more strongly on the QW position than is the case for hot electrons. The combination of the experimental measurements and Monte-Carlo simulations demonstrates the importance of Auger recombination processes which result in the production of hot holes.