Characterization of Sinusoidal Gating of InGaAs/InP Single Photon Avalanche Diodes

We report sinusoidal gating of InGaAs/InP single photon avalanche diodes (SPAD) operated at wavelength of 1310 nm with high photon detection efficiency (PDE) and low dark count rate (DCR). At a gating frequency of 80 MHz and temperature of 240 K the DCR and PDE were 15.5 kHz and 55%, respectively. The slope of DCR versus PDE increases with higher laser repetition rate. There are two mechanisms that contribute to this trend. The first is due to the lower afterpulse probability associated with a lower laser repetition rate. The other is due to the RC effect, which is illustrated by an equivalent circuit that includes a model of the SPAD. We also show that relative to gated passive quenching with active reset (PQAR) for fixed PDE, sinusoidal gating yields lower afterpulsing rates for the same hold-off time. This is explained in terms of the integrated pulse shape and the resultant charge flow. The afterpulse probability, P-a, is related to the hold off time, T, through the power law, P-a proportional to T(-alpha)where alpha is a measure of the detrapping time in the multiplication region.