Quantum technologies and quantum computing offer exciting new possibilities but also significant challenges that must be overcome to achieve their potential, including the need for fundamental microwave metrology at cryogenic temperatures to support the booming quantum technology industry. The SuperQuant project will establish novel metrological and scientific tools for the measurement of microwave signals in circuits in-situ in cryogenic environments down to the millikelvin range using a combination of superconducting, semiconducting, integrated and conventional photonics, and plasmonic techniques. This includes the development of a quantum standard of microwave power and a quantum-traceable cryogenic sampling oscilloscope with 1 THz bandwidth and an optically integrated quantized arbitrary waveform generator that will enable energy- and cost-efficient generation of thousands of microwave signals at cryogenic temperatures.

Objectives

1. To develop an optically integrated Josephson Arbitrary Waveform Synthesizer (JAWS) with a bandwidth exceeding 100 GHz, including the development of different ultrafast cryogenic optoelectronic converters based on semiconducting and plasmonic techniques. This is a prerequisite for establishing JAWS as a standard tool of QT outside NMIs by allowing cost- and energy-efficient systems with many output signals and with a bandwidth exceeding 100 GHz.
2. To develop a quantum-traceable cryogenic 1 THz sampling oscilloscope utilising optoelectronic techniques for in-situ waveform measurements inside cryostats with sub‑picosecond time resolution. To calibrate the oscilloscope with JAWS and to provide the first direct time-domain demonstration of the pulse quantization effect of Josephson junctions.
3. To develop and validate classical microwave S‑parameter measurement capability for microwave devices and components inside dilution refrigerators enabling traceable vector network analysis to be performed at temperatures below 100 mK. To evaluate the accuracy of these techniques on passive and active components.
4. To model and develop novel superconducting quantum sensor technology and sensors for measurements of microwave power in the frequency range 1 GHz – 12 GHz in-situ in superconducting circuits in cryogenic environments, including a full uncertainty estimation to validate the power sensors.
5. To facilitate the take up of the technology and measurement infrastructure developed in the project by end users in quantum technologies, the metrology community, national metrology institutes, research laboratories, and standards developing organisations (such as IEC).