Why is there a need for a new type of cable in the quantum industry? To make qubits in a quantum system work, we need to go to extremely low temperatures. Another word you may have heard for these ultracold systems is cryogenic systems. And working in this domain is not like making a cable that also works in your freezer. The cables that Delft Circuits produce do their job at a temperature that is ~270° lower than the freezing point of water. And hence the name of the product Cri/oFlex® – Cryogenic i/o which is flexible!

But there are more reasons to design a new type of cable. Traditionally, Coax-cables were used in quantum systems. These cables you may know from bringing in your TV signal. “Coax-cables work with several circular layers through which signals can be sent. This works well for high-frequency signals, which we also use in quantum systems. The only thing is that you need a multitude of cables, and this makes it not very scalable. For example, if you want to use components to amplify or weaken a signal, this cannot be integrated into the cable.”

These issues are solved by using another type of cable. “We do not work with coaxial cables but with striplines. And this has several advantages. First, the size of the cable is a lot smaller. You can also use multiple cables next to each other. This means that we can use a multitude of channels per cable. Also, we can integrate components in the cable, like the filters named before. This combined makes these cables more scalable, and this can be applied in quantum systems.”

Julia Lekanne dit Deprez (Instrument maker, Delft Circuits) at the Delft Circuits lab.

So, we thought, all the quantum systems need cables and a lot of them. And we asked ourselves how we can wire qubits in a different way than with coax-cables, which were designed for the telecom industry and not for the quantum industry.

-Daan Kuitenbrouwer, COO & Founder at Delft Circuits.

For the future, the scope of Delft Circuits is wider than just cabling. “We want to be a player who manufactures and designs i/o application for a wide range of quantum systems and cryogenic systems. With i/o application, we do not only mean cables but also interfaces and components, all necessary to successfully connect components of quantum systems. Our goal is to learn a lot about cryogenic applications to help as many parties as we can. And the more parties we help, the further our systems improve.”

The journey to work on the cables that Delft Circuit now produces already started some years ago. “I’m always confused if we started at 17 or 18 May 2017, so to be careful, we started in May 2017.” As Daan was studying the field of Fluid Mechanics, he met Sal via a mutual friend in Delft. Sal is the other founder of Delft Circuits. Daan always had the idea of starting a business and the quantum industry was a new field in which a lot more room was present for new projects.

Sal already had a great idea for a business in the field of quantum and he had a company where Daan started as an intern. And as time progressed, this internship grew to the business that Delft Circuits now is. But without the third person, Paulianne Brouwer, Delft Circuits wouldn’t be the company that it is today. She is the commercial brain behind the company. She broadened the view of Daan and Sal, and made it clear that there also is an important commercial aspect to designing a contribution for the quantum industry.

As this founding story contains an element of coincidence, it is not the only element that makes Delft Circuits the grown-up company with 25 employees that it is today. The idea to start on i/o applications and cables is a carefully crafted strategy.

“The idea comes from looking at the value chain in a developing industry. In the beginning, there are parties who build an entire system. At a certain point, all the sub-components need to meet higher demands and more components are being introduced. At a certain point, an industry emerges from parties who supply individual components, which was the case in 2015/2016. So, we thought, all the quantum systems need cables and a lot of them. And we asked ourselves how we can wire qubits in a different way than with coax-cables, which were designed for the telecom industry and not for the quantum industry,” says Daan.

And as we now have progressed for some years, the quantum industry does need cables, a lot of them. The team at Delft Circuits works hard in the lab, but they also make time to celebrate real ‘eureka’-moments. And as more cables are needed, more ‘eureka’-celebrations will come.