Long range, RF space communications do not meet anymore the bandwidth requirements or power constraints of future NASA missions. Optical communications offer the potential to dramatically increase the link bandwidth and decrease the emitter power. High-bandwidth, long-range optical communications require reliable high-gain, photon-counting detectors operated at moderate cooling with high detection efficiency, large aperture, sub-nanosecond temporal resolution, low intrinsic noise, and capability to handle large optical background. These requirements have not been met yet by single detector designs. We propose to develop a novel large area, photon-counting detector in infrared, operated with moderate cooling, gain greater than 10^6, detection efficiency greater than 50%, 100 MHz saturation counting rate, at least 500 MHz bandwidth, and configurable area. The approach is to develop compact, photon-counting detector arrays based on designs processed in high-volume manufacturing with validated reliability and infrared converters processed on large silicon wafers. This innovation provides a simple solution to high-bandwidth ground-space and space-space optical communications by mitigating optical aperture -- additive noise requirements. In Phase I, we will investigate the integration of the infrared converter into the photon detector processing flow, and will develop the electronics to increase the detector bandwidth and its saturation-counting rate.