Patent ID: 11274962

Abstract:
An apparatus, method and system for resolving an n-number of photons from an optical source multiphoton event, the apparatus includes a cryostat includes a single-pixel superconducting nanowire single-photon detector (SNSPD) configured to receive an optical signal and therefrom produce a corresponding electrical signal, and a current bias source configured to supply a bias current to the SNSPD. The apparatus further includes a low-noise amplifier configured to produce a low-noise amplified electrical signal from the electrical signal, a signal processing circuit configured to receive the low-noise amplified electrical signal having a waveform rising edge of an n-number photon event to produce either a time-differentiated electrical signal by processing the waveform rising edge with a differentiating circuit to generate a differentiated peak corresponding to the n-number photon event, or a time-to-amplitude electrical signal by processing the waveform rising edge with a precision timing circuit to generate a rise time measurement corresponding to the n-number photon event. The apparatus further includes an amplitude discriminating device configured to determine an integer n-number photon event based on measuring a value of the n-number photon event.