Self-consistent calculation of mode spectra and modulation response in wurtzite GaN quantum-well lasers

The photon rate-equation formalism is used to evaluate the multimode photon density, the output lasing power, and the modulation frequency response in pseudomorphically strained wurtzite GaN quantum-well lasers. The formalism is based on a self-consistent methodology that couples an envelope function (or k/spl middot/p) Hamiltonian with Poisson´s equation. From this approach, we consider (1) the band structure under the influence of large piezoelectric fields and with many-body effect; and (2) the stimulated and spontaneous emissions for each Fabry-Perot mode. Our calculations predict a threshold current density of approximately 1 kA/cm/sup 2/ and an intrinsic 3-dB modulation bandwidth of 11.7 GHz at 40-mW output power for a 50-/spl Aring/ pseudomorphically strained GaN-Al/sub 0.2/Ga/sub 0.8/N single-quantum-well (SQW) laser. Our estimation of the threshold current density represents the theoretical limit and is compatible with recent experimental results in InGaN multiple-quantum-well (MQW) lasers.