1,894 research outputs found
Quantum information processing with space-division multiplexing optical fibres
The optical fibre is an essential tool for our communication infrastructure
since it is the main transmission channel for optical communications. The
latest major advance in optical fibre technology is spatial division
multiplexing (SDM), where new fibre designs and components establish multiple
co-existing data channels based on light propagation over distinct transverse
optical modes. Simultaneously, there have been many recent developments in the
field of quantum information processing (QIP), with novel protocols and devices
in areas such as computing, communication and metrology. Here, we review recent
works implementing QIP protocols with SDM optical fibres, and discuss new
possibilities for manipulating quantum systems based on this technology.Comment: Originally submitted version. Please see published version for
improved layout, new tables and updated references following review proces
Measurement-device-independent quantum key distribution over untrustful metropolitan network
Quantum cryptography holds the promise to establish an
information-theoretically secure global network. All field tests of
metropolitan-scale quantum networks to date are based on trusted relays. The
security critically relies on the accountability of the trusted relays, which
will break down if the relay is dishonest or compromised. Here, we construct a
measurement-device-independent quantum key distribution (MDIQKD) network in a
star topology over a 200 square kilometers metropolitan area, which is secure
against untrustful relays and against all detection attacks. In the field test,
our system continuously runs through one week with a secure key rate ten times
larger than previous result. Our results demonstrate that the MDIQKD network,
combining the best of both worlds --- security and practicality, constitutes an
appealing solution to secure metropolitan communications.Comment: 17 pages, 4 figure
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