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

A theoretical investigation of the optical gain of electrically pumped intersubband lasers is presented. Using a prototype four-level near-infrared (1.55_μm) triple quantum well structure, self-consistent numerical simulations of the rate equations, energy density equations, optical gain and spontaneous emisson spectra of triple quantum well structures have been implemented at temperatures of 100 K and 300 K. It is predicted that the threshold currents of such lasers are significantly smaller than those for mid-infrared quantum cascade lasers.