Nitrogen effect on optical gain and radiative current density for mid-infrared InAs(N)/GaSb/InAs(N) quantum-well laser

Dilute-nitride InAsN/GaSb/InAsN “W” laser structure is theoretically investigated and compared with similar nitride-free InAs/GaSb/InAs “W” structure. The two laser diodes, to be grown on (0 0 1) InAs substrate, are designed to operate at 3.3 μm at room temperature. Their performances are evaluated in terms of modal gain and radiative efficiency characteristics deduced from optical gain calculation. We find that the inclusion of nitrogen in the laser active region improves optical gain performances leading to peak gain values of the order of 1000 cm−1 for typical injected carrier concentration of 1.5×1018 cm−3. Modal gain value equal to 70 cm−1 can be achieved and radiative current density inferior to 100 A/cm2 is predicted. These results demonstrate that the dilute-nitride InAsN/GaSb/InAsN laser structure is very attractive for room temperature operation in the midwave infrared domain.