Dependence of optical gain on crystal orientation in wurtzite–GaN strained quantum-well lasers

Optical gains in wurtzite–GaN strained quantum-well (QW) lasers are estimated theoretically for various crystallographic directions. The calculation of the valence subbands is based on the k⋅p theory, where deformation potentials are determined by a semiempirical tight-binding method. It is found that the gains in GaN strained QW lasers with non-(0001) orientations, particularly around the (101̄5) orientation, are markedly high and anisotropic, unlike those in (0001)-oriented lasers.