Intersubband gain without global inversion through dilute nitride band engineering

We investigate the possibility of interconduction band gain without global inversion by engineering the conduction bandeffective masses so that the upper lasing subband has an effective mass considerably smaller than the lower lasing subband that could not be obtained in conventional III-V materials. We recover the expected dispersive gain shape for similar masses and contrasting results if the effective masses characterizing the relevant subbands are very different.