A consistent trend in infrared imaging systems is a drive towards smaller pixel pitches in focal plane arrays. In this work, we present an extensive numerical study on how dark current, quantum efficiency, and modulation transfer function are affected when reducing the pixel pitch in SWIR InGaAs pixel arrays. From the results, we propose the introduction of diffusion control junctions into the pixel sub-architecture to lower dark current and improve modulation transfer function, with a minor decrease in specific detectivity.