Fibre optical sensor for C₂H₂ gas using sealed arc fusion spliced gas filled PBGF reference cell

Abstract

It is of great importance to develop gas sensing techniques which are selective, quantitative, fast-acting and not susceptible to poisoning. Spectroscopic optical gas sensors, especially those capable of remote sensing over optical fibres, are highly attractive for fast real-time detection and measurement of many gases [1]. One highly selective optical gas sensing method is correlation spectroscopy (CS) [2], in which a reference sample of target gas is held fixed within the interrogation system to act as a spectral reference, and is then compared with the spectrum of the test gas to obtain the measurement. We have suggested that a Photonic Bandgap Fibre (PBGF), filled with the target gas, provides a very effective and compact reference, with a clear advantage over traditional linear cells, which are bulky, intricate, fragile, difficult to align and expensive [3]