Optimization of the structural parameters in GaInNAs/GaAs quantum-well lasers

The optical gain characteristics as a function of the structural parameters of compressively strained GaInNAs/GaAs QW lasers with a well width of 80 A are investigated by using the multiband effective-mass theory. The relationship between the In and the N contents required to maintain a wavelength of 1.3 mu m shows that the addition of In reduces the N composition. The differential gain decreases with increasing N composition and begins to saturate when the N composition exceeds about 0.01. The transparency and the threshold carrier density are shown to continuously increase with increasing N composition. This is mainly attributed to the increase in the electron effective mass when N is added. The optimum N composition to obtain higher laser performance is found to be about 0.023.