Gated InGaAs detector characterization with sub-picosecond weak coherent pulses

Time-Bin Superposition Methods for DPS-QKD

“…However, with non-ideal SPDs, the optimal value against all attacks is N = 3 [11]. We observe this by the increase in dark counts and afterpulsing, leading to a deterioration in secure key rate as N increases [21]. The power splitters in the Type-A scheme introduce an extra loss.…”

“…The QKD testbed was also used to investigate the effect of excess bias voltage, gate width and hold-off time on the dark count rate (DCR) and afterpulse noises of a gated InGaAs single-photon detector (SPD) [21]. This helped in improvising the QBER for all 4 possible phase modulation patterns.…”

“…However, this method reduces the QBER of a system [24], but at a cost of a reduced sifted key rate, as shown in Fig. 11 to DCR, afterpulse probability and timing jitter were estimated from our previous work on gated SPD characterization [21].…”