Heterogeneous integration of single InAs/InP quantum dots with the SOI chip using direct bonding

Quantum information processing with photons in small -footprint and highly integrated silicon -based photonic chips requires incorporating non -classical light sources. In this respect, self -assembled III -V semiconductor quantum dots (QDs) are an attractive solution, however, they must be combined with the silicon platform. Here, by utilizing the large -area direct bonding technique, we demonstrate the hybridization of InP and SOI chips, which allows for coupling single photons to the SOI chip interior, offering cost-effective scalability in setting up a multi -source environment for quantum photonic chips. We fabricate devices consisting of self -assembled InAs QDs embedded in the tapered InP waveguide (WG) positioned over the SOI-defined Si WG. Focusing on devices generating light in the telecom C -band compatible with the low -loss optical fiber networks, we demonstrate the light coupling between InP and SOI platforms by observing photons outcoupled at the InP-made circular Bragg grating outcoupler fabricated at the end of an 80 pm -long Si WG, and at the cleaved edge of the Si WG. Finally, for a device with suppressed multi -photon generation events exhibiting 80 % single photon generation purity, we measure the photon number outcoupled at the cleaved facet of the Si WG. We estimate the directional on -chip photon coupling between the source and the Si WG to 5.1 %.