How the Moon Impacts Subsea Communication Cables: Conclusions, Acknowledgments, and References

Written by seismology | Published 2024/08/21
Tech Story Tags: oceanic-seismology | optical-oceanic-seismology | fiber-micro-bending | optical-phase-distortions | chromatic-dispersion | fiber-optic-sensing | tidal-latency-variations

TLDRThe study experimentally measured phase variations of an RF signal transmitted through a subsea cable between Japan and the US, revealing that tidal water pressure variations stretch the cable. This contradicts the loose tube model, showing that even minimal friction between the fiber and tube affects cable length. The results demonstrate a strong correlation between tide levels and cable length changes over daily and weeklong periods.via the TL;DR App

Author:

(1) Lothar Moeller, SubCom, Eatontown, NJ 07724, USA, [email protected].

Table of Links

Abstract and Introduction

GPS Long-Term Stabilized RF Phase Meter

Simple and Accurate models for tides

Latency Variations on Transpacific Cable

Poisson effect on pressurized cables

Conclusions, Acknowledgments, and References

6. CONCLUSIONS

For the first time we experimentally studied arrival phase variations of an RF signal on an optically looped-back carrier between Japan and the US. Our measurement suggests that cable length variations induced by water pressure, which depends on the tides across the pacific, stretch the fiber. This contradicts a ‘loose tube model’ for cables. The inherent coupling between the fibers and the loose tube, though this friction is very small, allows for transmittal of tension and tinily stretches them by a few ppb. We found a strong correlation between averaged tide levels and the arrival phase over daily periods. Larger offsets appear during weeklong recordings. It is surprising how long-term stable cables are but, then again, it’s remarkable how much tides cycle their length on a daily basis.

Acknowledgements

The author would like to thank R. Ray, W. Patterson, S. Bernstein, S. Abbott, B. Bakhshi, and S. Hunziker for supporting this work.

7. REFERENCES

[1] G. Marra, C. Clivati, R. Luckett, A. Tampellini, J. Kronjäger, L. Wright, A. Mura, F. Levi, S. Robinson, A. Xuereb, B. Baptie, D. Calonico, “Ultrastable laser interferometry for earthquake detection with terrestrial and submarine cables.” Science, eaat4458, (2018).

[2] M. Newland, M. Cantono, M. Salsi, V. Kamalov, V. Vusirikala, Z. Zhan, “SubHertz Spectral Analysis of Polarization of Light in a Transcontinental Submarine Cable,” ECOC 2020, Brussels, (2020).

[3] Li Wang, Y. Wang, J. Wang , F. LI, “A High Spatial Resolution FBG Sensor Array for Measuring Ocean Temperature and Depth,” Photonic Sensors, (2018).

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[5] Z. Zhan, “Distributed Acoustic Sensing Turns Fiber‐Optic Cables into Sensitive Seismic Antennas,” Seismological Research Letters. 91, pp.1–15, (2020).

[6] R.D. Ray, (2013), “Precise comparisons of bottom-pressure and altimetric ocean tides,” J. Geophys. Res. Oceans, 118, pp. 4570– 4584, (2013) doi:10.1002/jgrc.20336. https://agupubs.onlinelibrary.wiley.com/doi/ epdf/10.1002/jgrc.20336

[7] R.D. Ray, “A Global Ocean Tide Model From TOPEX/POSEIDON Altimetry: GOT99.2,” NASA/TM-1999-209478, (1999) https://ntrs.nasa.gov/citations/19990089548.

[8] A. Bertholds, R. Dandliker, “Deformation of Single-Mode Optical Fibers UnderStatic Longitudinal Stress,” JLT, vol. LT-5, No. 7, pp. 895-900, (1987).

[9] Richard G. Budynas and Ali M. Sadegh, “Roark's Formulas for Stress and Strain,” McGraw-Hill Companies, ISBN 9781260453751.

This paper is available on arxiv under CC BY 4.0 DEED license.


Written by seismology | Uncovering the secrets of the Earth's core, Seismology shapes resilient foundations for a sustainable tomorrow.
Published by HackerNoon on 2024/08/21