Limits of measurable perturbation rate in time-expanded phase-sensitive OTDR
Time-expanded phase-sensitive (TE-)ΦOTDR has emerged as a novel distributed acoustic sensing technology that fills the performance gap between typical ΦOTDR and OFDR. Centimeter resolution over kilometer range with kHz sampling rate have been made readily available, while demanding a reduced MHz det...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Universidad de Alcalá (UAH) |
| Repositorio: | e_Buah Biblioteca Digital Universidad de Alcalá |
| Idioma: | inglés |
| OAI Identifier: | oai:ebuah.uah.es:10017/65339 |
| Acceso en línea: | http://hdl.handle.net/10017/65339 https://dx.doi.org/10.1109/JLT.2024.3426036 |
| Access Level: | acceso abierto |
| Palabra clave: | Rayleigh scattering Dual frequency comb Phase modulation Dynamic range Distributed acoustic sensing Electrónica Electronics |
| Sumario: | Time-expanded phase-sensitive (TE-)ΦOTDR has emerged as a novel distributed acoustic sensing technology that fills the performance gap between typical ΦOTDR and OFDR. Centimeter resolution over kilometer range with kHz sampling rate have been made readily available, while demanding a reduced MHz detection bandwidth. This particular performance makes use of a specialty dual frequency comb, where one comb is used as probe and the other one as reference, and their repetition rates have a quasi-integerratio (QIR). In this work, we perform, for the first time to our knowledge, a comprehensive analysis of the limits of measurable perturbation (comprising the dynamic range) of TE-ΦOTDR, paying special attention to the QIR scheme. We show that the dynamic range of regular TE-ΦOTDR is similar to that of typical phase-demodulation ΦOTDR. However, the particularities of the QIR scheme intrinsically reduce the dynamic range. We set the conditions to determine the maximum detectable perturbation based on the Carson's rule. The minimum measurable perturbation in the QIR scheme is related to the processing noise induced by the sample reordering in a time-varying fiber. Finally, we present a novel post-processing algorithm that mitigates such processing noise, hence improving the sensitivity (and therefore the dynamic range). With the proposed processing method, we experimentally demonstrate a fourfold improvement in performance of the QIR system with respect to the state of the art, delivering an impressive sensing rate of 108 interrogated points per second with a sensitivity of −44 dB ref. 1μεε2/Hz and a detection bandwidth of only 100 MHz. |
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