A Cost-Effective Distributed Acoustic Sensor Using a Commercial Off-the-Shelf DFB Laser and Direct Detection Phase-OTDR

A Cost-Effective Distributed Acoustic Sensor Using a Commercial Off-the-Shelf DFB Laser and Direct Detection Phase-OTDR

We propose and experimentally demonstrate the use of cyclic pulse coding for enhanced performance in distributed acoustic sensing based on a phase-sensitive optical time-domain reflectometry ( <inline-formula> <tex-math notation="LaTeX">$\phi$</tex-math></inline-formul...

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Bibliographic Details
Main Authors: Yonas Muanenda, Claudio J. Oton, Stefano Faralli, Fabrizio Di Pasquale
Format: Article
Language:English
Published: IEEE 2016-01-01
Series:IEEE Photonics Journal
Subjects:
Fiber optics sensors
Rayleigh scattering
lasers
linewidth
Online Access:https://ieeexplore.ieee.org/document/7355285/
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Summary:We propose and experimentally demonstrate the use of cyclic pulse coding for enhanced performance in distributed acoustic sensing based on a phase-sensitive optical time-domain reflectometry ( <inline-formula> <tex-math notation="LaTeX">$\phi$</tex-math></inline-formula>-OTDR) using direct detection. First, we present a theoretical analysis showing that to make cyclic pulse coding effective in <inline-formula> <tex-math notation="LaTeX">$\phi$</tex-math></inline-formula>-OTDR, the laser linewidth and stability must be optimized to simultaneously guarantee intrapulse coherence and interpulse incoherence. We then confirm that commercial off-the-shelf distributed feedback (DFB) lasers can satisfy these conditions, providing coding gain consistent with theoretical predictions. By externally modulating such lasers with cyclic pulse coding, we demonstrate a distributed acoustic sensor capable of measuring vibrations of up to 500 Hz over 5 km of standard single-mode fiber with 5-m spatial resolution with &#x223c;9-dB signal-to-noise ratio (SNR) improvement compared with the single-pulse equivalent. We also show that the proposed solution offers sensing performances that are comparable to similar sensors employing highly coherent and stabilized external cavity lasers and a single-pulse <inline-formula> <tex-math notation="LaTeX">$\phi$</tex-math></inline-formula>-OTDR.
ISSN:1943-0655

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