ALOHA - Adaptive Large-capacity Optical-infrared High-dynamic-range Array

The ALOHA (Adaptive Large-capacity Optical-infrared High-dynamic-range Array) project addresses the limitations of current infrared (IR) imaging systems for Earth observation, wildfire detection, and remote sensing. Traditional Readout Integrated Circuits (ROICs) struggle with limited charge capacity, high noise at low flux, and excessive power dissipation at high flux, making it difficult to capture high-temperature scenes (300K–1600K) without saturation or image degradation. ALOHA introduces an innovative Residue Digital Pixel ROIC with in-pixel digital counters, achieving orders of magnitude larger well depths and per-pixel autonomous gain control to optimize signal-to-noise ratio (SNR). Key innovations include: • Per-pixel autonomous gain control, dynamically adjusting gain for optimal noise performance across varying flux levels. • Per-pixel autonomous anti-saturation control, preventing saturation without external adjustments. • Overflow bit monitoring, extending dynamic range indefinitely. • Low-voltage detector shunt circuitry, significantly reducing power dissipation from high-flux pixels. A preliminary 20µm pixel layout with 24 counter bits demonstrates a 16Te⁻ well capacity, achieving an unprecedented 230dB dynamic range. Power consumption remains below 100mW for a 2048 × 1024 array at low flux and under 400mW for high flux, making it suitable for low-SWaP (Size, Weight, and Power) spaceborne and UAV applications. Under SBIR Phase II, ALOHA will complete ROIC design, fabricate a test chip at a CMOS foundry, and conduct performance characterization. This technology is positioned for NASA’s FireSense, NOAA wildfire monitoring, and DoD ISR applications, with commercial potential in remote sensing and industrial monitoring.