Superconductor Science and Technology, 33, 11, 113001 (2020)
A review of the theory of bi-SQUIDs and the experimental studies of bi-SQUID-based devices is presented. The reported output voltage linearity of the fabricated devices (~40 to 45 dB) is much higher than that observed for dc SQUIDs (~20 dB). Recent numerical simulation evidence indicates that the linearity can be further improved to at least 60 to 70 dB. Results from a wide, multi-parameter optimization analysis are considered in the form of parameter domains for the voltage-response linearity. Thermal–noise influence, load impact and interfacing requirements are examined. Potential applications of the devices are discussed.