Analysis of optical gain and threshold current density of 980 nm InGaAs/GaAs compressively strained quantum well lasers

The valence hole subbands, optical gain spectra and threshold current density of InGaAs/GaAs compressive-strained quantum wells (QWs) were studied using a numerical approach. We found that a higher In composition in the quantum well and a thicker well give longer emitting wavelength; a narrower well and higher In composition lead to higher TE mode peak gain. The result also shows a suitable combination of In composition, QW thickness and number of QWs should be selected to achieve low threshold current density.