Zurich Instruments Parametric Pump Controller. Credit: Zurich Instruments

It’s no secret that obtaining the lowest possible level of noise is critical in building quantum computers. And one of the key areas that engineers look at is the circuitry to readout the qubit state for measurement. For this reason, engineers designing superconducting or spin qubit quantum processors can often choose to use parametric amplifiers for amplifying the readout signals after they are detected. These amplifiers can provide a significantly lower noise figure because they operate by varying the capacitance in a varactor diode rather than using resistance elements that generate thermal noise as used in a more traditional transistor amplifier. The result will be lower noise when reading out qubit status resulting in improved measurement fidelity and fewer errors.

To facilitate the use of parametric amplifiers, Zurich Instruments has introduced their SHFPPC parametric amplifier controller that generates the necessary pump signals and active pump tone cancellation so that parametric amplification can be used. It is meant to work with their SHFQA Quantum Analyzer or the SHFQC Qubit Controller in superconducting or spin qubit based processors as shown in the diagrams below:

Diagram of How a Parametric Amplifier is Used in a Quantum Processor. Credit Zurich Instruments
Diagram Showing How the SHFPPC Would Be Used in a Quantum Processor. Credit Zurich Instruments

The unit is available to support either 2 channels or 4 channels, but since many of the newer designs now have multiple qubits per readout channel, the number of qubits that can be readout with this technique will be greater. Additional information about this new product can be found in a news release provided by Zurich Instruments here, a web page and video describing the product here, and a data sheet that can be found here.

August 3, 2022