Leveraging a SiPh Mid-IR platform for integrated thermal source and detector to measure CO2 and CH4 levels, AEOLUS

We will present the advancements in AEOLUS, an H2020 project centered on sensing air quality and numerous gases, developing an integrated and miniaturized solution in Silicon photonics (SiPH). Traditional spectroscopic solutions, while reliable, are often bulky and costly, whereas we follow an integrated photonics solution for robust, miniaturized, and cost-effective systems. The integrated sensors NDIR spectroscopy in the mid-infrared (mid-IR), using suspended waveguide as a sensing element, graphene-based photodetectors for broadband and low power detection. The presented solution leveraged a broadband mid-IR source (thermal) that is cost-efficient and integratable and can greatly expand the applications of photonic integrated circuits (PICs). Thermal incandescent sources are advantageous over other mid-IR emitters based on semiconductor materials in terms of compatibility with PICs, manufacturing costs, and bandwidth. The 2D material used is consistent with the detector, i.e. graphene, a semi-metallic two-dimensional material. The demonstrated graphene mid-IR emitters integrated with photonic waveguides are considered for the mid-IR region relevant to absorption peaks of the gases under investigation for the purposes of air quality. A coupling efficiency of up to 68% is estimated with estimated emitter temperatures up to 1000°C [1], covering the mid-IR region. The overall concept of AEOLUS also includes a Silicon protective capping lid to safeguard the integrated devices on the chip, assembled at the wafer scale. Results from CO2 and CH4 gas detection using AEOLUS suspended waveguides, at 4.2μm and 3.2μm, respectively, will also be shown (leveraging ideal mid-IR absorption spectral peaks for these gases).