Comparative Study of Distributed Acoustic Sensing Responses in Telecommunication Optical Cables

Abstract

Distributed Acoustic Sensing (DAS) transforms conventional optical fibres into large-scale acoustic sensor arrays. While existing telecommunication cables are increasingly considered for DAS-based monitoring, their performance depends strongly on cable construction and strain transfer efficiency. In this study, the relative DAS signal amplitudes of three commercial telecommunication optical cables were experimentally compared using a benchtop Rayleigh backscattering-based interrogator under controlled laboratory conditions. By maintaining a constant temperature and ensuring no additional strain changes from the outside environment, we guaranteed that only strain-induced variations from acoustic excitations were measured. The results show clear differences in signal amplitude and signal-to-noise ratio (SNR) among the tested cables. The Microcable consistently produced the highest spatial peak amplitude (up to 0.029 a.u.) and SNR (up to 79), while the Duct cable reached 0.00268 a.u. with mean SNR ≈ 32. The Anti-Rodent cable showed low signal amplitude (0.0018 a.u.) but exhibited a high mean SNR (≈111) driven by an exceptional low noise floor in one of the runs. These findings reflect the variations in mechanical coupling between the fibre core and external perturbations and provide practical insights into the suitability of different telecom cable types for DAS applications, supporting informed choices for future deployments.

Keywords: acoustic monitoring; distributed acoustic sensing (DAS); infrastructure monitoring; optical fibre sensing; telecommunication cables.

Figure 1

Different telecommunication cables tested for DAS response: (a) Anti-Rodent cable, (b) Duct cable, and (c) Microcable.

Figure 2

The 1 Hz square-wave excitation signal (±5 V, 50% duty cycle) used to drive the vibrator during the 5–6 s vibration period within the 15 s data acquisition window.

Figure 3

Experimental setup, (a) real and (c) schematic showing the optical cable embedded in a rigid foam block and excited by a 1 Hz vibrator, with the DAS interrogator (NBX 7000 series, Neubrex Co., Ltd.) used for signal acquisition, and (b) top view of the vibrator and actuator rod location relative to the foam and cable.

Figure 4

DAS response of the Anti-Rodent Cable: (a) Trend Graph showing the temporal variation in signal amplitude during the 15 s acquisition period with 1 Hz excitation applied between 5 and 10 s; (b) Single Graph representing the corresponding amplitude–distance profile (in a.u.) extracted from the vibration peaks.

Figure 5

DAS response of the Duct Cable: (a) Trend Graph showing periodic peaks associated with the 1 Hz vibration; (b) Single Graph showing the spatial amplitude distribution along the sensing distance with a prominent response near the excitation region.

Figure 6

DAS response of the Microcable: (a) Trend Graph displaying six distinct vibration peaks corresponding to the 1 Hz excitation window; (b) Single Graph showing a sharp and localized amplitude peak near the excitation point, indicating efficient strain transfer.

Figure 7

Comparative DAS responses of the three tested telecommunication cables showing amplitude as a function of distance. The inset is focused curves.

Figure 8

(a–c) Spatial amplitude–distance responses (Single Graphs) for the Anti-Rodent, Duct, and Microcable cables, respectively, each showing three repeated experimental runs (Exp 1–3). Insets display the corresponding Trend Graph excerpts illustrating the temporal excitation cycles.

Figure 9

Error-bar plot of the mean temporal peak amplitude for each cable, with standard deviation across the three runs shown as uncertainty.