Avalanche current read-out circuit for low-jitter parallel photon timing

A circuit for single-photon avalanche diode (SPAD) current read-out, for photon timing applications, is proposed. The circuit consists of a single-transistor transimpedance amplifier with a gigahertz bandwidth: the feedback loop fixes the SPAD anode voltage and allows obtaining a high time resolution with a very high equivalent current threshold (almost 700 μA). The transimpedance stage is followed by a lowpass filter that reduces the crosstalk of other on-chip detectors and makes the designed structure suitable for multi-detector systems. The presented discrete components prototype achieves a state-of-the-art resolution of 34.4 ps full width at half maximum, has negligible crosstalk between the different pixels and opens the way for the development of an integrated structure with a large number of channels.