Rahme Matthew, Tuthill Peter, Betters Christopher, Large Maryanne, Leon-Saval Sergio
Sydney Astrophotonics Instrumentation Laboratory, School of Physics, The University of Sydney, Sydney, NSW, 2006, Australia.
Institute of Photonics and Optical Science, School of Physics, The University of Sydney, Sydney, NSW, 2006, Australia.
Sci Rep. 2024 Apr 30;14(1):9939. doi: 10.1038/s41598-024-59841-7.
Optical cross-correlation is a technique that can achieve both high specificity and high sensitivity when deployed as the basis for a sensing technology. Offering significant gains in cost, size and complexity, it can also deliver significantly higher signal-to-noise ratios than traditional approaches such as absorption methodologies. In this paper, we present an optical cross-correlation technology constructed around a bespoke customised Fiber Bragg Grating (FBG). Exploiting the remarkable flexibility in design enabled by multiple aperiodic Bragg gratings, optical filters are devised that exactly mimic the absorption features of a target gas species (for this paper, acetylene ) over some waveband of interest. This grating forms the heart of the sensor architecture described here that employs modulated optical cross-correlation for gas detection. An experimental demonstration of this approach is presented, and shown to be capable of differentiating between different concentrations of the target gas. Furthermore these measurements are shown to be robust against interloper species, with minimal impact on the detection signal-to-noise arising from the introduction of contaminant gases. This represents is a significant step toward the use of customised FBGs as low-cost, compact, and highly customisable photonic devices for deployment in gas detection.
光学互相关是一种作为传感技术基础时能够实现高特异性和高灵敏度的技术。它在成本、尺寸和复杂性方面有显著优势，与吸收法等传统方法相比，还能提供更高的信噪比。在本文中，我们展示了一种围绕定制的光纤布拉格光栅（FBG）构建的光学互相关技术。利用多个非周期布拉格光栅带来的显著设计灵活性，设计出了在感兴趣的某些波段精确模拟目标气体（本文为乙炔）吸收特性的光学滤波器。这种光栅构成了此处所述传感器架构的核心，该架构采用调制光学互相关进行气体检测。本文给出了这种方法的实验演示，结果表明它能够区分目标气体的不同浓度。此外，这些测量结果显示出对干扰物种具有鲁棒性，引入污染气体对检测信噪比的影响最小。这代表着朝着将定制FBG用作低成本、紧凑且高度可定制的光子器件用于气体检测迈出了重要一步。
