Analysis of linewidth enhancement factor for compressively strained AlGaInAs and InGaAsP quantum well lasers

Abstract

We have compared and analyzed theoretical investigation for the possibility of extreme reductions in the linewidth enhancement factor (α-factor) in strained layer quantum-well (QW) lasers between AlGaInAs and InGaAsP material. Valence band effective masses and optical gain in both types of QW lasers under compressive strain have been calculated using 4 × 4 Luttinger–Kohn Hamiltonian. We have used Kramers–Kronig relations to calculate the refractive index change due to carrier induced. The α-factor was up to 1.61 times smaller in AlGaInAs QW than in InGaAsP QW laser. The material differential modal gain and carrier induced refractive index change was found to be approximately 1.38 times larger and 1.15 times smaller respectively, in the previous material QW than in the latter QW laser. We also compared our results to the previously reported results for both QWs lasers.