A 32x32 pixel FLASH laser radar system incorporating InGaAs PIN and APD detectors

Abstract

We report on the demonstration of an InGaAs PIN and Avalanche Photodiode (APD) based 3-dimensional imaging system. The system utilizes a unique LADAR readout integrated circuit (ROIC) designed to operate using either PIN or APD based devices fabricated on a common cathode substrate. In addition to a digital range count that is output from each of the 1024 pixels, on-chip signal processing enables sub-six inch range resolution in a single FLASH image. The uniformity of the breakdown voltage, gain, and dark current of the InGaAs APDs fabricated for this demonstration greatly simplifies the ROIC architecture, as input offset voltage trimming is unnecessary. The ROIC architecture enables advanced LADAR applications such as first pulse suppression, programmed range interrogation, and return pulse shape sampling enabling dramatic improvements in range accuracy using advanced ranging algorithms.