Fig. 7.

Key milestones in silicon-based IQP. On-chip quantum interference and integrated CNOT gate on SiO2. Adapted with permission from [138], copyright 2008, AAAS. Integrated silicon SNSPD. Adapted with permission from [139], copyright 2012, NPG. The first integration of single-photon sources with quantum circuits on silicon. Adapted with permission from [140], copyright 2014, NPG. Chip-to-chip entanglement distribution system between two silicon chips. Adapted with permission from [141], copyright 2016, OPG. On-chip generation of six photons. Adapted with permission from [142], copyright 2017, OPG. The fully programmable two-qubit quantum processor on silicon [143], large-scale silicon IQP device comprising over 670 optical components. Adapted with permission from [18], copyright 2018, AAAS. The tunable AlGaAs-on-insulator (AlGaAsOI) MRR entangled-photon-pair source and all-on-chip quantum photonic circuits. Adapted with permission from [144], copyright 2021, APS. Topologically quantum entanglement emitter with a high tolerance of fabrication. Adapted with permission from [145], copyright 2022, NPG