QRC Seminar Series: Prof. André Xuereb

Quantum-secured communication, by which I mean quantum key distribution married to traditional telecommunications systems, is emerging as a next-generation technology for ultra-secure communication. In Malta we have embarked on a series of projects in recent years to understand better how to use existing optical telecommunication infrastructure for building a quantum key distribution service. In this talk I wish to walk through a few of these projects and present some of the more interesting, and perhaps unexpected, results that we have obtained, starting with something that few people in quantum communications may have considered.

In the first part of this talk I discuss our recent results, 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 quantum entanglement between Malta and Sicily over the telecommunications network using polarisation-entangled photon pairs.