Gas mapping based-on dual microcomb driven nanomaterial functionalized fiber Bragg grating string

Abstract Gas detection, encompassing both species identification and concentration quantification, is a critical capability. However, within a compact photonic chemical sensing unit, the simultaneous realization of these two objectives still remains elusive. Here, leveraging silicon photonics as the foundational platform, we introduce a high-precision multi-species gas mapper that integrates advances in nanoscience and fiber sensing. In this scheme, on-chip Kerr soliton dual-microcombs simultaneously drive and demodulate a network of nanomaterial-functionalized micro fiber Bragg grating (μFBG) detectors. This on-chip & on-fiber hybrid system achieves individual identification for 12 gas components with remarkable sensitivity. Within this single-laser-source, single-fiber architecture, responses across diverse nanomaterial-functionalized μFBGs are inherently independent, enabling each microcomb-line-driven sensor to exhibit high specificity and sensitivity to its target gas, attaining a record-low detection limit of 24.3 parts per billion (ppb) in single-shot measurements and 2.1 ppb post-averaging. Furthermore, the system enables high-fidelity fingerprint analysis of complex gas mixtures, with a maximum measurement error below 2.27%. This synergistic fusion of chip-scale dual-microcomb photonics with nanomaterial-enhanced optical sensor arrays represents a significant cross-disciplinary advancement, paving a way towards intelligent, miniaturized opto-chemical analysis platforms.