  Photon-number-resolving (PNR) detectors are a key enabling technology in
photonic quantum information processing. Here, we demonstrate the PNR capacity
of conventional superconducting nanowire single-photon detectors by performing
ultra-high-resolution time-tagging of the detector-generated electrical pulses.
This method provides a viable approach for PNR with high detection efficiency
and a high operational repetition rate. We present the implementation of such a
PNR detector in the telecom C-band and its characterization by measuring the
photon-number statistics of coherent light with tunable intensity.
Additionally, we demonstrate the capabilities of the detection method by
measuring photon-number correlations of non-classical states.
