Xanadu, Imec Partner on Developing Photonic Qubits

Article By : Nitin Dahad

The partnership focuses on fabricating ultra-low loss, highly uniform silicon nitride circuits used in error-corrected photonic qubits.

Xanadu, the photonic quantum computing specialist, will partner with the Belgian research center Imec to develop the next generation of photonic qubits based on ultra-low loss silicon nitride waveguides.

Toronto-based Xanadu was founded in 2016 to develop technology using light particles in quantum computers to perform extremely fast and previously impossible computations at room temperature. The company’s founder and CEO, Christian Weedbrook, said the advantages of the photonics approach include the ability to leverage pre-existing foundries and off-the-shelf optical components. Another advantage is the ability to link photonic chips for scaling a quantum computer up to 1 million qubits.

Imec-SiN wafer with photonics integrated circuits
Silicon nitride enables the generation of squeezed states, which replace single photons as the basis for synthesizing qubits. Image shows a SiN wafer with photonics integrated circuits. (Source: Imec)

Xanadu’s quantum machine utilizes photonic qubits based on squeezed states – a special type of light generated via chip-integrated silicon photonic devices. Particles of light are used to carry information through photonic chips rather than electrons or ions used by other approaches. Xanadu said its photonic approach offers the benefits of scalability to 1 million qubits via optical networking, room temperature computation and the ability to leverage Imec’s existing process technology.

Zachary Vernon, who heads Xanadu’s hardware team, stressed the advantages of working with the technology R&D center based on Leuven, Belgium: “One of the most critical challenges in building a photonic quantum computer is finding the right fabrication partner that can simultaneously deliver cutting-edge process development and volume production of high performing photonic chips. Imec is one of the few semiconductor R&D centers that does advanced technology R&D on advanced 200-mm and 300-mm lines, as well as volume manufacturing on their 200-mm line.”

That translates into fabrication of up to 1,000 wafers per year per customer on a few platforms, Vernon added, “including ultralow-loss photonic platforms. The seamless transfer offered by Imec of new processes to production is especially critical for rapid scaling of our technology.”

Added Weedbrook: “Working with Imec will help us build the right foundation based on fault tolerance and error-correctable qubits.”

Squeezed states

Competing platforms for photonic quantum computing traditionally rely on single photon sources made from silicon waveguides. Those platforms suffer from non-deterministic operation. Using silicon nitride enables the generation of squeezed states, which replace single photons as the basic resource for synthesizing qubits. Squeezed states are deterministically generated and can be used to produce error-resistant qubits called GKP states.

When multiplexed and implemented in Xanadu’s architecture, the approach is said to offer a more promising path to fault-tolerant quantum computing. Amin Abbasi, Imec’s business development manager, noted that the center’s silicon nitride photonics platform initially developed for communications applications “is finding its way towards other advanced applications like quantum computing.”

Xanadu closed a $100 million Series B funding round in May led by Bessemer Venture Partners along with new investors Capricorn, Tiger Global, BDC Capital and In-Q-Tel. The funding will help Xanadu build a quantum computing module. The “fault-tolerant module is the size of a few conventional server racks and will be the key building block to reaching 1 million qubits and [for] solving meaningful problems, leading to the opening up of a new global market,” Weedbrook predicted.

Over the last several years, Xanadu claims it has consistently doubled its qubit count, providing access via its photonic quantum cloud platform. The company has also released two open-source software products: PennyLane, a hardware-agnostic standard for quantum machine learning; and Strawberry Fields, a full-stack platform for photonic quantum computing. The tools are designed to provide developers, customers and researchers with access to computational tools used to create new algorithms while designing products aimed at solving real-world problems.


This article was originally published on EE Times.

Nitin Dahad is a correspondent for EE Times, EE Times Europe and also Editor-in-Chief of embedded.com. With 35 years in the electronics industry, he’s had many different roles: from engineer to journalist, and from entrepreneur to startup mentor and government advisor. He was part of the startup team that launched 32-bit microprocessor company ARC International in the US in the late 1990s and took it public, and co-founder of The Chilli, which influenced much of the tech startup scene in the early 2000s. He’s also worked with many of the big names—including National Semiconductor, GEC Plessey Semiconductors, Dialog Semiconductor and Marconi Instruments.


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