Description: NASA has a requirement for a large-area, high-quantum-efficiency, high-throughput optical receiver for ground-, air-, and space-based LIDAR systems. A radiation-hardened direct detection analog LIDAR receiver will be developed to address this need in the proposed STTR program. The rad-hard LIDAR receiver will be based upon a high gain (M > 1000), low excess noise (k ~ 0.02) InGaAs APD technology with high quantum efficiency (>80%) between 1000-1600 nm, deployed in a 61-element segmented array with a 600-um-diameter aggregate sensitive area. Segmentation of the detector area will minimize pixel capacitance, reducing amplifier noise and enabling GHz-class bandwidth. In Phase I, the proposed hexagonal APD array will be fabricated and hybridized to a custom fanout board for operation with discrete amplifiers. In the Phase II effort, a custom low-noise readout integrated circuit will be developed to mate directly to the hexagonal array, enabling higher sensitivity and higher bandwidth due to reduced interconnect parasitics. At the end of Phase II, the APD receiver will be integrated into a LIDAR test bed by the Electro-Optical Systems Laboratory at Georgia Tech for evaluation in a 6-month measurement campaign. Voxtel anticipates that its technology will enter the program at TRL=4, finish Phase I at TRL=5, and exit the Phase II program at TRL=7.

Benefits: The innovation has numerous dual-use applications in US military, industrial and commercial markets, including 3D modeling and site survey, autonomous navigation, automotive cruise control and obstacle avoidance, and robotics. Military applications include navigation and targeting for manned and unmanned systems, including fixed- and rotary-winged platforms, ground-based vehicles, and weapon mounts, as well as helmet-mounted low-light-level imaging.

The proposed low-noise optical receiver technology is applicable to a large number of NASA applications, including lidar atmospheric profiling, laser ranging, ladar navigation and hazard avoidance, and free-space optical communications.