Measurement-device-independent quantum key distribution coexisting with classical communication

Abstract

The possibility for quantum and classical communication to coexist on the same fibre is important for deployment and widespread adoption of quantum key distribution (QKD) and, more generally, a future quantum internet. While coexistence has been demonstrated for different QKD implementations, a comprehensive investigation for measurement-device independent (MDI) QKDa recently proposed QKD protocol that cannot be broken by quantum hacking that targets vulnerabilities of single-photon detectors -is still missing. Here we experimentally demonstrate that MDI-QKD can operate simultaneously with at least five 10 Gbps bidirectional classical communication channels operating at around 1550 nm wavelength and over 40 km of spooled fibre, and we project communication rates in excess of 10 THz when moving the quantum channel from the third to the second telecommunication window. The similarity of MDI-QKD with quantum repeaters suggests that classical and generalised quantum networks can co-exist on the same fibre infrastructure. Key rate (R ) Data rate (in Gbps) Key rate for 2x20km Co-propagating (1310nm) Key rate for 2x20km Bidirectional (1310nm) Key rate for 2x40km Co-propagating (1310nm) Key rate for 2x40km Bidirectional (1310nm) Key rate for 2x20km Co-propagating (1532nm) Key rate for 2x20km Bidirectional (1532nm) Key rate for 2x40km Co-propagating (1532nm) Key rate for 2x40km Bidirectional (1532nm) Key rate experimental 2x20 km Bidirectional Key rate experimental 2x40 km Bidirectional Key rate (R ) Data rate (in Gbps) Key rate for 2x20km Co-propagating (1310nm) Key rate for 2x20km Bidirectional (1310nm) Key rate for 2x40km Co-propagating (1310nm) Key rate for 2x40km Bidirectional (1310nm) Key rate for 2x20km Co-propagating (1532nm) Key rate for 2x20km Bidirectional (1532nm) Key rate for 2x40km Co-propagating (1532nm) Key rate for 2x40km Bidirectional (1532nm) Key rate experimental 2x20 km Bidirectional Key rate experimental 2x40 km Bidirectional Key rate (R ) Data rate (in Gbps) Key rate for 2x20km Co-propagating (1310nm) Key rate for 2x20km Bidirectional (1310nm) Key rate for 2x40km Co-propagating (1310nm) Key rate for 2x40km Bidirectional (1310nm) Key rate for 2x20km Co-propagating (1532nm) Key rate for 2x20km Bidirectional (1532nm) Key rate for 2x40km Co-propagating (1532nm) Key rate for 2x40km Bidirectional (1532nm) Key rate experimental 2x20 km Bidirectional Key rate experimental 2x40 km Bidirectional Key rate for 2x20km Co-propagating (1310nm) Key rate for 2x20km Bidirectional (1310nm) Key rate for 2x40km Co-propagating (1310nm) Key rate for 2x40km Bidirectional (1310nm) Key rate for 2x20km Co-propagating (1532nm) Key rate for 2x20km Bidirectional (1532nm) Key rate for 2x40km Co-propagating (1532nm) Key rate for 2x40km Bidirectional (1532nm) Key rate experimental 2x20 km Bidirectional Key rate experimental 2x40 km Bidirectional Key rate (R ) Data rate (in Gbps) Key rate for 2x20km Co-propagating (1310nm) Key rate for 2x20km Bidirectional (1310nm) Key rate for 2x40km Co-propagating (1310nm) Key rate for 2x40km Bidi...

Gigahertz measurement-device-independent quantum key distribution using directly modulated lasers

“…Our results suggest that >1 Mbps secure key rates are possible over metropolitan/access network distances of up to 25 km and we note that the MDI-QKD architecture is well suited for building QKD networks in a star topology [8], with the high-cost SPDs in a central location and many users possessing only a compact lowcost transmitter. Recent results have also demonstrated multiplexing of classical and quantum signals in MDI-QKD, even revealing that MDI-QKD offers improved resilience to Raman noise compared to conventional pointto-point QKD [32]. MDI-QKD is therefore posed to play a valuable role in the real-world exploitation of quantum communications.…”

The Evolution of Quantum Key Distribution Networks: On the Road to the Qinternet

“…Eriksson et al [250] demonstrated the joint propagation of a quantum channel located at 1549.5 nm and 100 classical data channels associated with an aggregate transmission rate of 18.3 Tb/s in the C-band, achieving a secret-key rate of 28.9 kbps over a 10 km SMF. Valivarthi et al [251] characterized the simultaneous operation of MDI-QKD with five 10 Gb/s bidirectional classical channels in the vicinity of the 1550 nm wavelength over the same fiber of 40 km length. In [103], the coexistence of a CV-QKD system with a classical channel operating in the C-band was demonstrated, and a secret-key rate of 300 kbps was attained for a link length of 13 km.…”

Deployed MDI-QKD and Bell-State Measurements Coexisting with Standard Internet Data and Networking Equipment

“…Fiber 1 was used for Alice's and Bob's transmissions (Tx) of the IP networks optical signals and qubits (Center Node reception, Rx). We chose this co-propagation configuration to minimize scattered light at the single photon detectors of the Center Node [52]. The qubit channel generated by the MDI-QKD system operated at 1310 nm wavelength and multiplexing the qubits with the IP data signals was achieved by a standard WDM multiplexer.…”

“…Over the last decade, numerous realizations of MDI-QKD have been shown, both in the lab and in the field [44][45][46][47][48][49][50][51]. However, so far only one laboratory study has examined how conventional optical communication signals may impact this protocol [52], which guides our development presented here: a field-deployed, multi-node quantum communication system, incorporating a BSM node and coexisting with conventional telecom equipment, signals and data traffic.…”