Interference of heralded single photons generated in silicon waveguide sources

Quantum interference between identical photons lies at the heart of our plan to construct a silicon photonic quantum computer. Several ground-breaking experiments have demonstrated the on-chip interference between photons generated in spiral [1] and ring resonator [2] sources. However, these two-photon experiments have relied on detecting the simultaneous arrival of a pair of photons from either source. In order that such experiments can be scaled-up, we require the multiplexing of probabilistic photon pair sources into an on-demand single photon source [3]. A first step towards this is to demonstrate heralded single photons from different sources will retain the purity and indistinguishability required to interfere with high visibility [4].

In our work we examine photon pair production by spontaneous four-wave mixing in a silicon waveguide source and determine the factors that limit the heralded two-photon interference visibility. We present a novel approach to modelling this generation process using the joint- temporal amplitude and compare our results with experimental data.

[1] On-chip quantum interference between silicon photon-pair sources, Nature Photonics 8, 104, (2014).

[2] Qubit entanglement between ring-resonator photon-pair sources on a silicon chip, Nature Communications 6, 7948, (2015).

[3] Active temporal and spatial multiplexing of photons, Optica 3, 127, (2016)

[4] Indistinguishable photon pair generation using two independent silicon wire waveguides, New Journal of Physics 13, 065005, (2011).