In a recent publication, Frederik Thiele et al. explored a technique to operate an SNSPD all-optically at cryogenic temperatures. SNSPDs are superconducting single-photon detectors required for quantum optical measurements. Cryogenic operation temperatures are needed for these single photon sensitive devices. Typically, superconducting detectors are operated in a cryostat. Coaxial cables are then used to transmit power and signals between the cryogenic detector and the room temperature measurement equipment. However, coaxial cables conduct a significant amount of heat in the cryostat which limits the cooling capacity of the cryostat. In this publication, we show a method to replace coaxial cables with optical fibers which has significantly lower heat load. To provide the superconducting detectors with the operation power, we convert light to electrical power with a cryogenic photodiode. Furthermore, we readout out the detection signal of the detector with light modulation of an electro-optical modulator. The combination of both techniques enables an all-optical operation of a SNSPD.
The paper is available open access at: https://doi.org/10.1364/OE.492035
