Figure 1

A nonlinear crystal is pumped at period $T$, resulting in the generation of photon pairs at random intervals. The idler photon is split off and detected, heralding the existence of the signal photon. The appropriate signal photon is then sent into a delay circuit, where it is delayed to the next rail at period $NT$.Reuse & Permissions

Figure 2

AMPP generation for $N=8$. A laser enters a series of beam splitters and delay arms designed to generate eight pulses at period $T$. The laser then pumps a nonlinear crystal (NLC) and emits an electronic triggering signal, which gates the heralding detector (D) and synchronizes the decision electronics. The photon pairs generated are split at a polarizing beam splitter (PBS), with the idler photon sent to the detector. The detector outputs a bit stream, which is read by the data processor (P). The processor outputs a bit stream to an ultrafast bit generator, which controls the switch, MZI1. The signal photon is sent to a delay line and is either rejected by MZI1 or transmitted to the active delay circuit. MZI2–5 are controlled by periodic clock cycles. $/n$ denotes the clock rate division by a factor of $n$ required to drive the modulators according to Table . Delays are denoted by $nT$ for $n=1,2,4$ and $T$ the pump period. Light is coupled on-chip by a tapered fiber (TF).Reuse & Permissions

Figure 3

(a) The total efficiency of our single-detector (red circles) and detector-array (green squares) protocol, and previous single-delay-arm time-multiplexing schemes assuming the same single-detector (blue diamonds) and detector-array (black triangles) protocol, ceteris paribus. This assumes current fabrication procedures, including ${\eta }_{\mathrm{sw}}=0.87$. (b) The same curves as in (a); however, assuming ${\eta }_{\mathrm{sw}}=0.98$. (c) $\langle {\eta }_{\mathrm{lin}}\rangle$ for different values of $\lambda$. The red, green, and blue curves assume last-photon selection, for $\lambda =0.02$, $\lambda =0.06$, and $\lambda =0.1$, respectively, while the black control curve does not. By last photon selection, the effect of linear loss can be reduced for large N.Reuse & Permissions

Figure 4

(a) Heralded Bell-state generation using four AMPP sources. Four photons are combined on two polarizing directional couplers (PDC) after having passed through $\pi /4$ polarization rotators (PR). Ports 1 and 4 contain the output state, which is projected onto a Bell state by measurement at the four heralding detectors. These components are analogous to those in bulk optics, and have been realized experimentally on SOI platforms. (b) Entanglement generation from two AMPP sources. Two orthogonally polarized photons interfere on a nonpolarizing directional coupler. Coincidence counting on the two output ports post-selects the state $|HV\rangle -|VH\rangle$.Reuse & Permissions