  We analyze internal device physics, performance limitations, and optimization
options for a unique laser design with multiple active regions separated by
tunnel junctions, featuring surprisingly wide quantum wells. Contrary to common
assumptions, these quantum wells are revealed to allow for perfect screening of
the strong built-in polarization field, while optical gain is provided by
higher quantum levels. However, internal absorption, low p-cladding
conductivity, and self-heating are shown to strongly limit the laser
performance.
