Creating and sharing knowledge for telecommunications

Seeing earthquakes and distributing entanglement on the international telecoms network


on 17-07-2018

André Xuereb, University of Malta

Date & Time: Thursday, July 17, 15:00
Location: Room P9, Mathematics Building, Instituto Superior Técnico, Lisbon


Abstract:

Detecting ocean-floor seismic activity is crucial for our understanding of the interior structure and dynamic behaviour of the Earth. However, 70% of the planet’s surface is covered by water and seismometers coverage is limited to a handful of permanent ocean bottom stations.

In the first part of this talk I discuss our recent results [1], where we showed that existing telecommunication optical fibre cables can detect seismic events when combined with state-of-the-art frequency metrology techniques by using the fibre itself as the sensing element. We detected earthquakes over terrestrial and submarine links with length ranging from 75 to 535 km and a geographical distance from the earthquake's epicentre ranging from 25 to 18,500 km. Implementing a global seismic network for real-time detection of underwater earthquakes requires applying the proposed technique to the existing extensive submarine optical fibre network.

In the second part of the talk I will discuss briefly how we distributed entanglement between Malta and Sicily [2] over the telecommunications network using polarisation-entangled photon pairs.

[1] http://science.sciencemag.org/content/early/2018/06/13/science.aat4458
[2] http://arxiv.org/abs/1803.00583

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