Miniature Mid-IR Spectrometer Based on a Ge-Si Photonic Integrated Circuit and a Linear Detector Array for Trace Gas Detection

Miniature spectrometers that enable energy-efficient and application-specific spectral sensing are key to developing applications such as distributed sensing systems, IoT and wearable devices, and mobile autonomous platforms, to enumerate a few. Crucially, optical methods, and specifically vibrational spectroscopy can allow for in-situ measurements of analytes, eliminating the need for sample transportation and subsequent laboratory processing or analysis. Photonic sensors may be arranged in the form of a wide-coverage network with multiple measurement points, allowing for fast reactions to changing environmental conditions. However, the development of a reliable, compact sensing system for the entire mid-infrared spectral range (e.g. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2-20 \mu \mathrm{m}$</tex> [1]) remains challenging due to the limited availability of light sources and light detectors, as compared to the visible and near-infrared ranges.