APL Photonics (Oct 2023)

Millimetric spatial resolution time-expanded ϕ-OTDR

  • Miguel Soriano-Amat,
  • Philippe Guay,
  • Hugo F. Martins,
  • Sonia Martin-Lopez,
  • Miguel Gonzalez-Herraez,
  • María R. Fernández-Ruiz,
  • Jerome Genest

DOI
https://doi.org/10.1063/5.0150991
Journal volume & issue
Vol. 8, no. 10
pp. 100803 – 100803-8

Abstract

Read online

Time-expanded phase-sensitive optical time-domain reflectometry is a distributed optical fiber sensing technology based on dual-frequency combs that allows for dynamic and high spatial resolution measurements while maintaining reduced detection requirements. Since the formalization of the technique, different experimental schemes have been satisfactorily tested, with a general performance of cm-scale spatial resolution over hundreds of meters. In this article, we present an optimized scheme with enhanced energy and spectral efficiencies that allows reaching 5 mm spatial resolution. As compared to previous experimental approaches, the presented architecture is based on a free-running dual comb setup generated through pure electro-optical phase modulation. Besides, the introduction of an optical hybrid in the detection stage allows for doubling the spatial resolution while keeping the refresh rate and the sensing range unchanged.