High field electronic transport through a strongly coupled superlattice (SL) with a shunting side layer is numerically studied using a drift-diffusion model that includes both vertical and lateral dynamics. The bias voltage corresponds to an average electric field in the negative differential conductivity region of the intrinsic current-field curve of the SL, a condition that generally implies space charge instability. Key structural parameters associated with both the shunt layer and SL are identified for which the shunt layer stabilizes a uniform electric field profile. These results support the possibility to realize a SL-based terahertz oscillator with a carefully designed structure. © 2010 American Institute of Physics.