Multiphysics analysis of chip and resonator designs for increased damage threshold of external cavity high-power laser diodes

We present a detailed analysis of multiphysics simulation results to evaluate the threshold for catastrophic optical damage (COD) of high-power laser diodes under misaligned external optical feedback. Three different chip designs are investigated: the non-injecting mirror concept, the non-absorbing mirror concept and the introduction of an additional energy barrier within the waveguide near the front facet. Furthermore, a modification of the external resonator that promises a lower sensitivity towards misalignments is considered. The dependence of the COD threshold on the additional design parameters (bandgap change, modification length, focal length) and the impact of the different approaches on electro-optical efficiency as well as beam quality are analyzed. Compared to the initial design, the different chip design concepts promise an increase of the achievable output power by 8%, 27% and 27% respectively, whereas the modified resonator fully prevents feedback-induced failure.