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7th SIG-NGN meeting blog: Stepping outside the frame

On February 15 2022, the Special Interest Group on Next Generation Network (SIG-NGN) held second of a series of virtual meetings. The meeting focused on the theme of “Stepping outside the frame” and covered non-packet and non-frame based services, with enlightening presentations on topics of earthquake detection using fibre networks and QUANT-NET (Quantum Application Network Testbed for Novel Entanglement Technology).

Dr Phillippe Jousset from GFZ Postdam, Germany, gave an insightful talk about earthquake detection using fibre optics networks. He gave an overview of principles of seismology and the importance of densification of the sensor and how different types of sensors are used to study earthquakes.  He explained different types of measurements that can be helpful to identify seismic activity. One the methods that is used across submarine cables is the Time delays measurement which based on measures the changes in propagation delays of the laser light travelling across the fibre. The changes in propagation delays are caused by environmental perturbation to the fibre, such as vibrations, acoustic noise, and temperature fluctuations.

Figure 1: Tele-seismic events on terrestrial optical links match with seismic station on land

Figure 1 shows the measurements or activity detected by the Optical link and a seismic station and these two measurements are quite similar so the detection of seismic activity over fibre link seems to be working quite well. 

Phillippe explained how the traditional sensors rely on discrete sensors placed on a pre-determined point. Whereas the distributed sensing doesn’t rely on a single sensor but instead utilises the optical fibre as sensor. This provides a continuous, real-time measurement along the entire length of a dark fibre optic cable. He gave details of DAS (Distributed Acoustic Sensing) where the fibre itself is the sensor, however this technique requires a dark fibre so no other services can run along side it.


Figure 2: Reykjanes Experiment


He provided details of an exciting experiment carried out in Iceland across a fibre cable between power plants in Reykjanes and Savarsengi in Iceland (see Figure 2).

Figure 3: DAS Traces

The distance between the two sites is about 15 KMs and using the DAS technique the experiment team was able to detect the cars travelling along the road. He explained how they can detect earthquakes using DAS traces from the fibre optics cable and their proposal to use submarine fibre optic cables as global geomonitor (see Figure 3 on the left).



Figure 4: Notional view of Quantum Internet

The second presentation by Inder Monga, Executive Director of ESnet, gave overview of QUANT-NET. This is a project about building basic building-blocks of Quantum Internet. Inder started with basic Quantum Principles, i.e., QUBIT, Superposition and Entanglement. He then gave a notional view of the Quantum Internet as shown in Figure 4 on the left.


He then explained the difference between QKD (Quantum Key Distribution) vs Quantum networking. The QKD uses quantum properties to exchange a private key used to encrypt/decrypt classical channels. Whereas the Quantum network or Quantum internet is used to exchange Quantum State between distributed Quantum Computers. This talk mainly focused on the Quantum networking rather than QKD.

Inder provided overview of the QUANT-Net project, the objectives of this project include developing a quantum networking testbed system to demonstrate the basic elements of distributed quantum computing and to design and implement scalable quantum network protocols, control and monitoring for testbed.

All presentations and the recording of the meetings are available on SIG-NGN wiki page.

The next SIG-NGN virtual meeting on the topic of edge technologies, titled “Reaching where the fibre can’t” will be held on the 23rd May 2022. Register to attend the event.

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