Optical anisotropy in semipolar (Al,In)GaN laser waveguides

In this work, the optical eigenmodes of a semipolar (Al,In)GaN laser diode are calculated. A full vectorial one-dimensional 4×4 transfer matrix method is used to correctly incorporate the influence of birefringence of the wurtzite crystal. Depending on the orientation of the laser waveguide relative to the c-axis, the eigenmodes show TE/TM- or extraordinary/ordinary polarization. The polarization direction of the eigenmodes is crucial for the performance of the laser, as it determines the relevant interband matrix elements for the optical gain.