Calibrating the Noise in Your Qubit Readout Lines

Our Quantum Team has developed a tool, the Cryogenic Variable-Temperature Noise Source, that can be used immediately for the optimization of quantum computer readout lines, and even for direct tests of how qubits behave when disturbed by noise.  

In most quantum labs, detecting the state of a qubit is done by sending and receiving weak microwave tones into a cryogenic refrigerator and strongly amplifying the output signal to boost the measurement fidelity as much as possible. At such small signal levels – even down to the limit of single photons – understanding and reducing noise added by the amplifier and other components becomes crucial.  

The development of the Cryogenic Variable-Temperature Noise Source supports world-leaders in quantum technology with their measurement challenges. Senior Scientist Russell Lake and the Bluefors Quantum Team (including Aleksi Lintunen, Volodymyr Monarkha, and Slawomir Simbierowicz) developed the Cryogenic Variable-Temperature Noise Source to improve the speed and accuracy of validating qubit readout lines. The tool goes inside the cryogenic environment and adds controlled amounts of noise to the signal paths to calibrate the intrinsic noise added by the amplifiers, cables, and all other components. Read the article (Editor’s Pick) on the development and application of the Cryogenic Variable-Temperature Noise Source in the Review of Scientific Instruments here The proof-of-concept was performed using a parametric amplifier supplied by a collaboration with VTT Technical Research Centre of Finland Ltd. 

In addition, the team also measured a new kind of amplifier that was made by NIST and FermilabThey observed noise performance at the quantum limit using the new method  the results are presented in Applied Physics Letters in March 2021. 

Contact our Sales team for more information on the Cryogenic Variable-Temperature Noise Source

Close-up of Cryogenic Variable-Temperature Noise Source installed in a Bluefors XLDsl System cryostat