Self-consistent optical gain and threshold current calculations for near infrared intersubband semiconductor lasers

A theoretical investigation of the optical gain of electrically pumped inte rsubband lasers is presented. Using a prototype four-level near-infrared (1 .55 mu m) triple quantum well structure, self-consistent numerical simulati ons of the rate equations, energy density equations, optical gain and spont aneous emisson spectra of triple quantum well structures have been implemen ted at temperatures of 100 K and 300 K. It is predicted that the threshold currents of such lasers are significantly smaller than those for midinfrare d quantum cascade lasers.