Chip-based devices improve practicality of quantum-secured communication

March 19, 2020

monstrated new chip-based devices that contain all the optical components necessary for quantum key distribution while increasing real-world security. The fast and cost-effective platform is poised to facilitate implementation of extremely secure data communication that can be used to protect everything from emails to online banking information.

Advances in computing technology will soon leave today's methods for encrypting online data vulnerable to eavesdropping. Quantum key distribution offers impenetrable encryption by using the quantum properties of light to generate secure random keys between users for encrypting and decrypting their online data. Although quantum key distribution is compatible with most fiber-optic networks, more robust and less expensive devices are needed to carry out this encryption method outside the lab.

In Optica, The Optical Society's (OSA) journal for high-impact research, the researchers report that secure quantum key exchange can be accomplished between two chip-based devices -- measuring just 6 x 2 millimeters -- potentially over a fiber network with links up to 200 kilometers long.

"Chip-based devices significantly reduce the barrier for widespread uptake of quantum-secured communication by providing a robust, mass-manufacturable platform," said research team leader Henry Semenenko from the University of Bristol, UK. "In the future, these devices will form part of a standard household connection to the internet that keeps our data secure regardless of advances in computing technology."

Reducing size and power needs

The new quantum key distribution devices are based on the same semiconductor technology found in every smartphone and computer. Instead of wires to guide electricity, they contain highly complex circuits that control the weak photonic signals of light necessary for quantum key distribution. Nanoscale components in the chips make it possible to drastically reduce the size and power consumption of quantum communication systems while maintaining high-speed performance vital for modern networks.

"With its densely packed optical components, our chip-based platform offers a level of precise control and complexity not achievable with alternatives," said Semenenko. "It will allow users to access a secure network with a cost-effective device the same size as the routers we use today to access the internet."

The researchers designed the new platform to facilitate citywide networks and drastically reduce the number of connections required between users.

"Our platform allows single users to connect to a centralized node that enables secure communication with every other user," said Semenenko. "As quantum networks develop, the centralized node will offer crucial infrastructure that will eventually support more complex communication protocols."

Demonstrating the devices

The researchers demonstrated their new chip-based devices with a proof of principle experiment in which they emulated a 200-kilometer fiber network at the University of Bristol Quantum Engineering Technology Labs. Using two independent chip devices, they showed that error rates and speed were comparable to state-of-the-art, commercial components.

"We showed that these chip-based devices can be used to produce quantum effects even when photons were generated by different devices," said Semenenko. "This is vital for quantum networks where each user will control their own devices that are distributed around a city."

The researchers plan to make the system more practical by developing application-specific hardware. They will then use the fiber-optic network in place around the city of Bristol to create a demonstration metropolitan network with many users.
Paper: H. Semenenko, P. Sibson, A. Hart, M. G. Thompson, J. G. Rarity, C. Erven, "Chip-Based Measurement-Device-Independent Quantum Key Distribution," Optica, 7, 3, 238-242 (2020). DOI:

About Optica

Optica is an open-access, journal dedicated to the rapid dissemination of high-impact peer-reviewed research across the entire spectrum of optics and photonics. Published monthly by The Optical Society (OSA), Optica provides a forum for pioneering research to be swiftly accessed by the international community, whether that research is theoretical or experimental, fundamental or applied. Optica maintains a distinguished editorial board of more than 60 associate editors from around the world and is overseen by Editor-in-Chief Prem Kumar, Northwestern University, USA. For more information, visit Optica.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit
Media Contacts:

Aaron Cohen
(301) 633-6773

The Optical Society

Related Quantum Articles from Brightsurf:

Theoreticians show which quantum systems are suitable for quantum simulations
A joint research group led by Prof. Jens Eisert of Freie Universit├Ąt Berlin and Helmholtz-Zentrum Berlin (HZB) has shown a way to simulate the quantum physical properties of complex solid state systems.

Quantum shake
There they were, in all their weird quantum glory: ultracold lithium atoms in the optical trap operated by UC Santa Barbara undergraduate student Alec Cao and his colleagues in David Weld's atomic physics group.

New evidence for quantum fluctuations near a quantum critical point in a superconductor
A study has found evidence for quantum fluctuations near a quantum critical point in a superconductor.

Quantum simulation of quantum crystals
International research team describes the new possibilities offered by the use of ultracold dipolar atoms

Quantum machines learn "quantum data"
Skoltech scientists have shown that quantum-enhanced machine learning can be used on quantum (as opposed to classical) data, overcoming a significant slowdown common to these applications and opening a ''fertile ground to develop computational insights into quantum systems''.

Simulating quantum 'time travel' disproves butterfly effect in quantum realm
Using a quantum computer to simulate time travel, researchers have demonstrated that, in the quantum realm, there is no 'butterfly effect.' In the research, information--qubits, or quantum bits--'time travel' into the simulated past.

Orbital engineering of quantum confinement in high-Al-content AlGaN quantum well
Recently, professor Kang's group focus on the limitation of quantum confine band offset model, the hole states delocalization in high-Al-content AlGaN quantum well are understood in terms of orbital intercoupling.

Quantum classifiers with tailored quantum kernel?
Quantum information scientists have introduced a new method for machine learning classifications in quantum computing.

A Metal-like Quantum Gas: A pathbreaking platform for quantum simulation
Coherent and ultrafast laser excitation creates an exotic matter phase with spatially overlapping electronic wave-functions under nanometric control in an artificial micro-crystal of ultracold atoms.

Quantum leap: Photon discovery is a major step toward at-scale quantum technologies
A team of physicists at the University of Bristol has developed the first integrated photon source with the potential to deliver large-scale quantum photonics.

Read More: Quantum News and Quantum Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to