2024 Volume 59 Issue 2 Pages 88-96
A single-flux-quantum circuit is a promising device for a cryogenic signal processor for a superconducting nanostrip single photon detector (SNSPD) due to its high-speed operation, low power dissipation, and low timing jitter. The cryogenic signal processor based on the SFQ circuits can sense the output signals of multi-pixel SNSPDs with low timing jitter in a low temperature stage, which provides an advanced SNSPD system such as a high-count rate system, a two-photon coincidence system, a single-photon imaging system, and so forth. We have developed and demonstrated some SNSPD systems using an SFQ signal processor in a 0.1-W Gifford-McMahon (GM) cryocooler. In this review, we introduce a cryogenic signal processor based on SFQ circuits for advanced SNSPD systems.