Distributed gas sensing with optical fibre photothermal interferometry

L. I.N. Yuechuan, L. I.U. Fei, H. E. Xiangge, JIN Wei, Min Zhang, Fan Yang, Hoi Lut Ho, T. A.N. Yanzhen, Lijuan Gu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

39 Citations (Scopus)


We report the first distributed optical fibre trace-gas detection system based on photothermal interferometry (PTI) in a hollow-core photonic bandgap fibre (HC-PBF). Absorption of a modulated pump propagating in the gas-filled HC-PBF generates distributed phase modulation along the fibre, which is detected by a dual-pulse heterodyne phase-sensitive optical time-domain reflectometry (OTDR) system. Quasi-distributed sensing experiment with two 28-meter-long HC-PBF sensing sections connected by single-mode transmission fibres demonstrated a limit of detection (LOD) of ~10 ppb acetylene with a pump power level of 55 mW and an effective noise bandwidth (ENBW) of 0.01 Hz, corresponding to a normalized detection limit of 5.5ppb.W/√Hz. Distributed sensing experiment over a 200-meter-long sensing cable made of serially connected HC-PBFs demonstrated a LOD of ~ 5 ppm with 62.5 mW peak pump power and 11.8 Hz ENBW, or a normalized detection limit of 312ppb.W/√Hz. The spatial resolution of the current distributed detection system is limited to ~ 30 m, but it is possible to reduce down to 1 meter or smaller by optimizing the phase detection system.

Original languageEnglish
Pages (from-to)31568-31585
Number of pages18
JournalOptics Express
Issue number25
Publication statusPublished - 11 Dec 2017

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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