Optical gain calculation of mid-infrared InAsN/GaSb quantum-well laser for tunable absorption spectroscopy applications

We report on optical gain calculations of a dilute-nitride mid-infrared laser structure designed to be grown on InAs substrate. The active region is composed of several strain-compensated type-II “W”-like InAsN/GaSb/InAsN quantum wells adapted to operate near 3.3 μm at room temperature. For typical injected carrier density σ = 1.1012 cm− 2, the theoretical laser structure performances reveal a gain value at around 1000 cm− 1 at 300 K, inducing a modal gain value equal to 50 cm− 1. Low radiative current densities lower than 100 A/cm2 are predicted, indicating that this dilute-nitride structure could operate at 300 K with small threshold current density.