Refractive index step and optical confinement in Ga0.86In0.14As0.13Sb0.87/Ga0.73Al0.27As0.02Sb0.98 double heterostructure lasers emitting at 2.2 mu m

Using theoretical fitting to measured transverse far field patterns in Ga_0.86In_0.14As_0.13Sb_0.87/Ga_0.73Al_0.27As_0.02Sb_0.98 DH lasers emitting at 2.2 mu m the authors estimated the value of the active layer refractive index as 3.78. This value, higher than assumed earlier based on theoretical calculations, ensures good optical confinement for this kind of heterostructure and provides a good theoretical fit with the authors´ experimental data of threshold current density against active layer thickness.