  Interband cascade lasers (ICLs) stand out due to their low threshold current
and minimal power consumption, rendering them viable sources for compact and
mobile devices in the mid-infrared. Since their first demonstration, they
experienced major performance improvements. Many of them originate, on one
hand, from technological enhancements and, on the other hand, also from
restricted numerical analysis. Encouraged by the impact of restricted models,
an ICL-specific simulation tool can lead to performance breakthroughs and a
better comprehension of governing mechanisms. Drawing from an evaluation of
existing tools designed for quantum cascade structures, we implemented a
self-consistent density matrix rate equation model generalized to simulate the
transport in both conduction and valence band heterostructures. Albeit the
extensive inclusion of the quantum effects, special care was taken to maintain
a high numerical efficiency. Our charge transport model additionally considers
optical field calculations, allowing for predictive calculations of
light-current-voltage (LIV) curves. We benchmark the model against
well-established ICL designs and demonstrate reliable performance
predictability. Additionally, we give detailed insights into device
characteristics extracted from our model. This ultimately allows us to deepen
our understanding of ICLs and define existing and generate novel designs.
