High-gain Low-excess-noise Linear-mode APD for Small-pitch Ladar

A high-sensitivity, narrow-field-of-view ladar receiver, optimized for long-range target detection and identification will be developed, characterized, and demonstrated.In Phase I avalanche photodetector (APD) and readout integrated circuit (ROIC) components were tested and validated. In Phase II, the pulse amplification, detection, and timing circuitry will be cast as a fine-pitch 1616-format array optimized for demonstrating the performance of the technology for U.S. Air Force targeting applications. To support multi-hit grayscale operation, circuitry to sample, store, and read out five times of arrival and pulse-amplitude data pairs per pixel per frame will be integrated into each pixel element. A matching single-carrier-multiplication APD array will be manufactured and hybridized to the new ladar ROIC. The resulting focal-plane array (FPA) will be characterized, demonstrating 3-cm range precision and 95% pulse-detection efficiency at signal levels of ~200 photons per pixel. The ladar receiver delivered to AFRL at the end of Phase II will support frame rates in the kHz, demonstrating compatibility with a step-stare architecture in which the field of view is scanned over a much higher-resolution field-of-regard at video frame rate.