Band-gap renormalization effects on 980 nm strained-layer InGaAs/AlGaAs quantum-well lasers

We calculate the optical gain and threshold current density of strained-layer InGaAs/AlGaAs quantum-well lasers with the band-gap renormalization effects taken into account. It is found that the band-gap renormalization shifts the lasing wavelength as much as 30 nm which is much larger than the allowed bandwidths, ±6 nm, of 980 nm Er-doped optical fiber amplifiers. We also try to optimize the graded-index separate-confinement- heterostructure optical waveguide layer in order to maximize the optical confinement factor and to reduce its fabrication dependence. The threshold current densities are calculated for the optimized structures for which the gain peak positions are predicted to be within the allowed bandwidths of 980 nm.