Figure 2
From: Photonic Readout of Superconducting Nanowire Single Photon Counting Detectors
Working principle of the SNSPD optical readout. (a) The superconducting SNSPD provides a low impedance path to ground so all the bias current flows through it. (b) When the SNSPD absorbs a photon, the developed hotspot resistance diverts the current into the readout, producing a voltage pulse that drives the modulator and shifts its resonance, therefore changing the transmitted light. (c) The passive reset circuit provides a low-impedance path to ground, allowing for the hotspot to thermally relax and for the SNSPD to go back to its superconducting state. CDECOUPLING = 100 pF, LRESET = 8 μH, RRESET = 50 Ω.
