The activity on integrated quantum optics focuses on actively multiplexing of heralded single photon sources[1], on single photon detectors detectors, on the manipulation of two-photon states[2], and the frequency conversion of single photons [3]. Currently, we rely mostly on SiN photonics ICs that we complement with other functional elements such as nonlinear materials[4] or semiconductors. Picture : The process of four-wave mixing is used to create pairs of correlated photons [5] or change their wavelength [3] (A). It benefits strongly from the filed enhancements in microcavities (B) and it can induce strong coupling between single photons inside a cavity (C)
[1] Frequency multiplexing for quasi-deterministic heralded single-photon sources in Nature communications
[2] Strong Nonlinear Coupling in a Si3N4 Ring Resonator in Physical Review Letters
[3] Ramsey interference with single photons in Physical Review Letters
[4] Integrated silicon nitride electro-optic modulators with atomic layer deposited overlays in Optics Letters
[5] Continuous wave photon pair generation in silicon-on-insulator waveguides and ring resonators in Optics Express