Work

InP-compatible InGaAs/GaAsSb type-II superlattice eSWIR FPA with 2.7 µm cutoff: radiometric calibration and 3D noise analysis

Year: 2026

Type: article

Abstract: Extended short-wave infrared (eSWIR) photodetectors and focal plane arrays (FPAs) are critical photonic components for LIDAR, hyperspectral imaging, and optical communication. However, the widespread adoption of eSWIR photonics has been constrained by the fundamental bandgap limit of InP-compatible materials (1.7 µ m cutoff), which restricts their detection window, and by the lack of standardized calibration methodologies for larger-format arrays. Here, we overcome these limitations by demonstrating an InP-compatible InGaAs/GaAsSb type-II superlattice (T2SL) FPA—a 1280 × 1024 array with a 2.7 µ m cutoff wavelength, 15- µ m pitch, and single-imager architecture. Critically, the FPA achieves a noise-equivalent temperature difference of 28.02 mK at 140 K with >95% uniformity, while extending the detection cutoff to 2.7 µm and enabling large-format eSWIR imaging. Furthermore, we establish and experimentally validate a physics-based radiometric calibration framework that quantitatively links blackbody radiation to FPA response voltage, addressing a critical gap in SWIR FPA characterization. An FPA-specific three-dimensional (3D) noise decomposition reveals that the proposed calibration framework effectively suppresses structured readout-induced fixed-pattern noise while leaving intrinsic detector noise unchanged, resulting in a peak post-calibration signal-to-noise ratio of 26.3 dB. These results establish InP-compatible InGaAs/GaAsSb T2SLs as a viable platform for next-generation eSWIR photonics, providing extended spectral coverage relevant to applications that were previously inaccessible with conventional InP-based detectors.

Source: Optics Express

DOI: 10.1364/oe.612263