Description: To satisfy NASA deep-space communications needs, a readout integrated circuit (ROIC) optimized for single-photon counting (SPC) freespace optical communications will be developed, which is optimized for acquisition, tracking, ranging, and reception of the 1064 nm – 1570 nm optical radiation used for freespace optical links. The ROIC will allow simultaneous recovery of photon time of arrival and spatial localization data that can be used for lasercom optical links, data recovery, and range measurements, even in the presence of high photon flux rate objects in the field of view. In Phase I, after developing a rigorous requirements document and confirming a controlled specification, a low-cost ROIC will be developed to couple to single-photon-counting detector arrays. The ROIC pixel circuits will be designed and simulated, as will key circuits, such as serializers, downsamplers, decision circuits, up/down counters, time-to-digital converters (TDCs), etc. When appropriate, circuits from existing ROICs will be demonstrated and characterized to show performance and proof of concept. At Phase I end, a preliminary design review will be conducted.

Benefits: NASA's Space Communications and Navigation (SCaN) Program Office identified optical communications as an important technology for NASA missions, allowing enhanced volume and quality of data returned from the farthest reaches of space to be achieved in order to prepare for future human deep-space exploration missions. Although several missions have validated optical communications from low-Earth and geostationary orbit, the unique challenges of deep-space optical links still require separate risk-retiring technology demonstrations before implementing inner orbit communication. There a number of NASA applications benefiting from the innovation, including using the single-carrier multiplication (SCM) APD arrays for LADAR autonomous navigation, docking, and landing systems, and in LIDAR instruments for atmospheric sciences. The primary focus of this effort is to develop the SCM-APD for space optical communications.

The innovation will enable low-SWAP space-based, free-space optical communications, terrestrial freespace optical communication, charge particle detectors, photon-counting, automotive LADAR, LIDAR, altimetry, time-resolved spectroscopy, fluorescent decay measurements, single-photon detectors, and auto- and cross-correlation.