Article author: Maurizio Di Paolo Emilio
Cryogenic cables could be the key to simplifying the design of quantum computers.
Delft Circuits has announced that it will participate in the Antarctic BICEP project in support of NASA’s Jet Propulsion Laboratory (JPL) at Caltech and other project partners. As part of the new camera, the JPL team decided to attach advanced cables from Delft Circuits to the telescope’s cryostat.
The JPL team will also replace the telescope’s sensors with a new Thermal Kinetic Inductance Detector (TKID), a superconducting detector that harnesses the properties of quantum mechanics. The infrastructure requirements are very similar to those needed to set up and measure qubits in quantum systems.
In recent years, there has been growing interest in quantum computing by large multinational groups, researchers, and start-ups. Today’s supercomputers, also known as high-performance computing (HPC) systems, are computationally intensive and are not yet capable of solving problems beyond a certain level of complexity.
Quantum computing approaches, on the other hand, are expected to overcome the current limitations of HPC, as computational power increases as the number of qubits used by a system increases.
Quantum computer design challenges
Creating a quantum computer presents an unprecedented design challenge, as individual qubits must be as stable as possible and unaltered by external agents. Depending on the type of technology used to implement qubits, it is often necessary to produce temperatures close to absolute zero to reduce noise as much as possible. As a result, quantum computing hardware is typically placed inside cryogenic dilution refrigerators.
The next challenge is to connect the control electronics, which normally operate at room temperature, with the low-temperature quantum devices. Given that next-generation quantum processors will be able to incorporate more than 1,000 qubits, this process requires very complex wiring.
Figure 1 below shows the details of a quantum computer, highlighting some of the intricate wiring involved in designing a quantum computer. A regular coaxial cable might be sufficient to deal with and read a few dozen qubits (at the cost of a non-negligible burden), but reducing physical size and heat conduction Both needs remain a need for higher density interconnects. dilution refrigerator.
Delft Circuits Solution
Founded in 2017 and headquartered in Delft, the Netherlands, Delft Circuits has developed a revolutionary quantum computer cable technology called Cri/oFlex. Initially created to solve the connectivity problem of a quantum computer prototype created as part of university research, the technology aims to create the perfect wiring for quantum computing. The result is a flexible microwave cable with the following properties:
- Shrinking form factors and making them scalable as the number of qubits increases
- Low thermal conductivity (< 4 μW heat load per channel at 3K – 0.7K)
- Ease of installation
- Integrated signal attenuation and filtering
- High durability
Cri/oFlex combines flexible cryogenic cables with standard RF connectors to create interconnect solutions that offer both single and multi-channel cabling.
Delft Circuits CEO and Co-Founder Sal Jua Bosman and Delft Circuits Head of Sales Artem Nikitin said: Interview with EE Times. “We are primarily focused on input/output systems, which have a variety of applications ranging from sensors to computers to biomedical sensing.”
As shown in Figure 2, the cable is made using a unique combination of polyimide and silver, resulting in a very thin stripline channel with high microwave performance and flexibility.
“We are making flexible, microwave and cryogenic cables. A cable that has all these properties at once is unprecedented,” said Nikitin and Bosman. .
Bosman adds: And cryogenic temperatures are what lies above. ”
Additionally, the cable integrates all filtering components (lowpass filter, bandpass filter, and attenuator) to overcome the challenges of conventional microwave engineering in cryogenics. Integrating all necessary components reduces potential points of failure, reduces installation time, and increases setup robustness.
Cri/oFlex Product Family
Delft Circuits offers three different product families based on the same technology, but with different specifications and performance. These products serve many types of applications such as quantum computing, astrophysics, optics, and instrumentation.
Cri/oFlex 1
These highly flexible microwave I/O cables meet the requirements of scanning probe microscopes and other vibration sensitive instruments. These cryogenic RF cables are extremely thin and flexible, allowing signal transmission with minimal vibration coupling. Therefore, the Cri/oFlex 1 series features microwave transmission lines as small as 0.3 mm and as small as 1 mm.
Cri/oFlex 2
These single channel microwave I/O cables are suitable for tight sample spaces in refrigerators. Due to their small size and reduced heat load, the number of microwave lines in the cryostat can be increased. Flexible RF cables are based on monolithic waveguides, and their phase stability is virtually insensitive to vibration and bending. Cri/oFlex technology is extremely flexible from room temperature to cryogenic temperatures.
Cri/oFlex 3
The Cri/oFlex 3 Series is the company’s flagship product designed for scalability. It uses a signal line with dispersion attenuation and integrated microwave signal conditioning, so there is little need for additional microwave components.
Due to its small volume and low heat load, Cri/oFlex 3 supports a large number of signal lines that can be installed inside a dilution chiller. The flexible cable contains up to 8 parallel channels with a channel-to-channel pitch of 1 mm and no microwave breakouts between stages.
Cri/oFlex use cases
Many Delft Circuits customers use microwaves at low temperatures. Among these customers is NASA’s JPL, where the research team uses astrophysics detectors to measure microwave background radiation from space.
“Detecting this radiation requires a sensitive microwave kinetic inductance detector (MKID) and uses our cable solution to read the signal,” said Nikitin and Bosman.
MKID devices couple with microwave frequency resonators to provide a high level of multiplexing. This allows reading up to 1,000 detector pixels using one of his MKID cables and microwave transmission measurements. Such detector arrays are now being scaled up to tens of thousands of pixels to enable high-resolution imaging.
These detector chips are usually installed at the bottom of the telescope, requiring a specially built cryostat with limited space and cooling capacity. Given the current trend of expanding such detector arrays, there is a need for MKID microwave cables that are compact, easy to install, and have low heat loads.
“One-third of our total revenue comes from quantum computing,” said Nikitin and Bosman. “Quantum computing is our first beachhead, but we are also thinking about other application areas for our products, such as astrophysics, STM and he AFM, biomedical imaging, which are very close to space applications.”
This article was originally published on EE Times.
Maurizio di Paolo Emilio I have a Ph.D. He has a PhD in Physics and is a Telecommunications Engineer. He has worked on various international projects in the area of gravitational wave research designing thermal compensation systems, X-ray microbeams, and space technology for communications and motor control. Since 2007 he has worked with several blogs and magazines in Italian and English as a technical his writer specializing in electronics and technology. From 2015 until 2018 he was Editor-in-Chief of his Firmware and Elettronica Open Source. Maurizio enjoys writing and speaking articles on power he electronics, wide his bandgap semiconductors, automotive, IoT, digital, energy and quantum. Maurizio is currently Editor-in-Chief of Power Electronics News and he is EEWeb’s European Correspondent for EE Times. He is the host of his PowerUP, a podcast about power electronics. In addition to many technical and scientific articles, he is the author of two of his Springer books on Energy Harvesting and Data Acquisition and Control Systems.
