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

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.

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