HYPRES, UMass connect cold superconductor low-power processors to the warm world

Elmsford, NY (March 16, 2018) — HYPRES partnered with the University of Massachusetts Amherst to complete a high-speed, energy-efficient digital data link between superconductor integrated circuits and room-temperature electronics. The work was conducted under a Small Business Technology Transfer (STTR) project, sponsored by the Office of Naval Research (ONR).

Superconductor ICs, based on single flux quantum (SFQ) logic, operate at 4 K with signal levels that are several orders of magnitude smaller than standard room-temperature electronics. This property makes superconductor electronics attractive for various applications that require high sensitivity, higher clock rates for faster sampling and higher speed logic, and can tolerate cryogenic operation. Transporting digital data to room temperature, however, has always been a challenge due to the need to balance the electrical and thermal requirements while providing a large amplification factor. By ensuring optimal use of low-power superconductor electronics, these faster, more energy-efficient, data links will maximize the functionality of an electronic system within the constraints of its size, weight, and power consumption.

The HYPRES-UMass team developed a hybrid temperature heterogeneous technology (HTHT) data link that distributes the necessary amplification among multiple temperature-distributed stages to optimize the overall link.

“Our approach was to start with the fastest superconductor output driver and connect it to a chain of cryogenic semiconductor amplifiers at different temperatures between 4K and 300K,” said Dr. Deepnarayan Gupta, president of HYPRES’ Digital-RF Circuits and Systems business division and the principal investigator of the project. “We have already reached 20 Gbps data rates per link using this approach, which is better than 14 Gbps data links achieved without any cryogenic semiconductor amplification. We are now working toward enhancing the data link rate as well as expanding the number of simultaneous channels with both electrical and optical approaches. Better data links are vitally important to the next generation of our Advanced Digital-RF Receiver (ADR) product line as well as for future applications, such as streaming high-speed data processing, for which superconductor electronics offer compelling solutions.”

The key technology in this HTHT data link was developed by professor Joseph Bardin’s group at UMass Amherst.

“We pursued two alternative designs, both using silicon-germanium bipolar transistors.” Bardin explained. “At cryogenic temperatures, these transistors produce higher gain and higher speeds. Through a careful design process, we have optimized the tradeoff between speed and power consumption for our cryogenic integrated circuits. Both designs have met our target performance metrics and now offer different alternatives to HYPRES’ system engineers.”

ONR has been a major sponsor of cryogenics and superconductor electronics during the past three decades. Dr. Deborah Van Vechten, ONR program officer, was one of the first to recognize the need for innovation to develop high-speed data links that also minimize power consumption.

“ONR encourages partnerships between university research groups and small businesses to harness innovative ideas into practical products,” she said. “This team has moved through the different phases successfully and has attracted external funding to augment the STTR investment. The HTHT data link is now ready for transition.”

About HYPRES
HYPRES, Inc., of Elmsford, NY, develops and commercializes superconductor integrated circuits (ICs) and systems that provide unparalleled performance advantages for government and commercial applications. The flagship product is the Advanced Digital-RF Receiver (ADR), comprising superconducting digital and mixed-signal ICs packaged on a COTS cryocooler. HYPRES also develops custom semiconductor ICs, high-performance analog RF circuits, and runs a complete niobium-based superconducting integrated circuit (IC) fabrication line. HYPRES has recently introduced the Integrated Cryoelectronics Test Bed (ICE-T), a turnkey laboratory test system requiring no liquid cryogen. It provides complete cryogenic infrastructure for broadband electrical testing of standard and custom high-speed superconducting integrated circuits at 4 K and above.