Carrier-induced lasing wavelength shift for quantum well laser diodes

Lasing wavelength was analyzed for quantum well laser diodes (QW-LD's) considering both the bandgap shrinkage effect and the band-filling effect. The bandgap shrinkage effect was calculated by the local density functional method, treating both electron and hole distribution self-consistently. Assuming no
k
-selection rule, the band-filling effect is larger than the bandgap shrinkage effect when the carrier density is high. The lasing wavelength shifts to the short side as the threshold carrier density increases. QW-LD's with a large threshold carrier density lase at very short wavelength corresponding to the transition between the second sublevel. However, this wavelength is still longer than that expected because of the bandgap shrinkage effect.