Single-photon-counting detectors optimal for NASA long-range freespace optical telecommunications will be developed. The proposed effort addresses NASA’s need for reliable sources of radiation-hardened 1064-nm- and 1550-nm-sensitive single-photon photoreceivers for deep-space communications. There has been previous investment in single-photon-sensitive detector arrays; InGaAs APD pixels operating in Geiger mode (GM) are the most popular single-photon detectors in this spectral range as they do not require cryogenic cooling. However, performance improvements are need in InGaAs GM-APD focal-plane arrays (FPAs), and multiple reliable suppliers need to be established. To address this need, two growth and fabrication campaigns will be conducted. Each five-wafer growth campaign will include: single-element devices of various diameters, small-sized arrays, and larger-format GM-APD arrays. Characterization of the variable-diameter single-element devices, as a function of temperature and area/volume ratio, will be performed to identify sources of dark counts. Testing of arrays will be used to establish breakdown voltage uniformity, optical crosstalk, and yield. The demonstration of the performance of working GM-APD devices will significantly reduce the risk of the Phase II effort. In Phase II, large-format GM-APD arrays will be fabricated and hybridized to an existing deep-space communications readout integrated circuit (ROIC).
NASA applications include: deep-space optical comms; lidar measures as called for by the 2017 Decadal Survey for Earth Science and Applications from Space (high priority for cloud/aerosol/ocean lidar); and future missions to Earth’s moon, Mars, Venus, Titan, Europa, and small bodies (e.g., asteroids and comets) calling for entry, descent, and landing sensor systems. Autonomous rendezvous, proximity operations, and docking are other NASA challenges to which a 3D lidar sensor is relevant.
The innovation has widespread use in military mapping, targeting, and surveillance and reconnaissance, as well as freespace optical communications. It has commercial use in quantum communications, freespace communications, mapping, and autonomous driver-assistance sensor (ADAS) and autonomous navigation systems.