Cisco has advanced its journey into quantum networks by unveiling Universal Quantum Switch, a working prototype designed to connect quantum systems from different suppliers.
For some time, Cisco – with a number of partners – has been working on distributed quantum networks that it believes could lay the groundwork towards a quantum computing internet defined by quantum computers, sensors and communication in the late 2030s.
Explaining the background to the launch, Cisco said current quantum computers are powerful but limited, operating at hundreds of qubits when real-world applications in healthcare, financial services and aerospace will need millions to achieve unheard-of speeds and technological breakthroughs. The company believes networking and connectivity are central to bridging that gap. The quantum future will not be built by any one company or any one technology. It will be built by connecting them all.
Specifically regarding the new technology, Cisco suggested that attempting to connect billions of people and tens of billions of devices with direct cables would be unmanageable, and that the internet became possible because classical switches could connect all of those endpoints through a shared, scalable network.
Yet given quantum computers encode information in different ways, until now, no switch could accept and translate between all major encoding modalities without destroying the quantum information in the process.
The Universal Quantum Switch is designed to address this challenge for the first time, routing quantum information while preserving it at room temperature, on existing telecom fibre, with a Cisco-patented conversion engine that translates between encoding modalities at input and output.
When two quantum computers need to share information, the Universal Quantum Switch does the same thing for quantum: accepts the signal in whatever modality it arrives, translates it into a common language for routing, and delivers it in the format the receiving system needs, without losing any quantum information along the way.
In addition, the technology is regarded as a critical milestone in quantum networking that addresses one of the most fundamental barriers to building a quantum network.
A Cisco-patented conversion engine at the heart of the quantum switch is said to allow the output modality to match an input or be an entirely different one, enabling the quantum switch to connect and translate between quantum systems that were never designed to talk to each other, a critical capability for building quantum networks that work across different suppliers and technologies.
Furthermore, it is designed to support all major quantum encoding modalities used to carry information. These include: polarisation, the orientation of light waves; the timing of light pulses (time-bin); frequency-bin, the colour or frequency of light; and the physical or spatial path. To date, the quantum switch has been experimentally validated with polarisation encoding. Support for time-bin and frequency-bin is built into the design and represents the next step in Cisco’s ongoing validation process.
Proof-of-concept experiments – using Cisco’s own entanglement source and single-photon detectors – are said to have found quantum information preserved through conversion in the switch with less than 4% degradation in quantum state fidelity and entanglement. This means maintaining the coherence that quantum networks require to function.
The tests also showed sub nano-second electro-optic switching, reconfiguring connections in as little as one nanosecond, and that the process is energy efficient, consuming less than one milliwatt of power.
As a working research prototype, Cisco sees the switch as a proof point in accelerating its full-stack quantum networking programme. It is designed to route quantum information between systems while preserving it, with a Cisco-patented conversion engine that translates between all encoding and entanglement modalities at input and output.
“Reaching this milestone is a pivotal moment for our quantum programme and a testament to the transformative potential of quantum networking,” said Vijoy Pandey, senior vice-president and general manager of Outshift, Cisco’s emerging technologies and incubation group.
“We’ve long recognised that connecting quantum systems is the key to achieving true scalability, and now we’ve taken a critical step toward making that vision a reality. While this is a significant achievement, it’s just the beginning. The road ahead is long, yet the impact of what we are building – and what is still to come – will be nothing short of profound.”
