ABL (Airborne Laser) Detection Sensor Improvements

To provide the Airborne Laser (ABL) precision ranging and 3-D track refinement capability for the next generation active ranging system (NGARS), Voxtel will develop an avalanche photodiode (APD) receiver. Unlike the original ARS, which uses a 10.6 µm CO2 laser, Voxtel’s InGaAs-based ARS receiver is designed for high-speed photon counting between 1.0 – 1.6 µm. Operation in the short-wave infrared (SWIR) allows the use of wider-bandgap detector materials with relaxed cooling requirements and the use of telecommunications industry semiconductor optoelectronics technology and manufacturing infrastructure. The large civilian market for lasers and detectors that operate at the eye-safe 1.55 µm fiber attenuation minimum ensures a stable and diverse manufacturing base to support NGARS technology, and market-driven improvements of yield, uniformity, cost, and performance. The advanced receiver technology developed by this program can readily be adapted to civilian applications. In Phase I, Voxtel demonstrated a monolithic multi-stage InGaAs APD design with gains exceeding 2000, with greatly reduced multiplication noise, and characteristics compatible with linear-mode SWIR single photon counting. In Phase II, Voxtel will develop a prototype 32×32 NGARS LADAR camera using improved variants of the multi-stage APD focal plane arrays (FPAs), including a custom readout integrated circuit (ROIC) with 30 cm range resolution.