Gain, differential gain and linewidth enhancement factor of GaInNAs/GaAs strained quantum well lasers

We present calculations of the material gain, differential gain and linewidth enhancement factor (alpha) for GaInNAs/GaAs quantum wells based on the free-carrier theory. We explore the effect of N composition on peak differential gain and transparency concentration. The nitrogen-induced conduction band non-parabolicity is accounted for through the band anti-crossing model, and valence band mixing effects and strain are treated exactly. The alpha factor is found to have similar values to those of the conventional material InGaAsP/InP, which is encouraging for the use of GaInNAs as the active material for a high speed emitter.