The demand for integrated photonic chips combining the generation and
manipulation of quantum states of light is steadily increasing, driven by the
need for compact and scalable platforms for quantum information technologies.
While photonic circuits with diverse functionalities are being developed in
different single material platforms, it has become crucial to realize hybrid
photonic circuits that harness the advantages of multiple materials while
mitigating their respective weaknesses, resulting in enhanced capabilities.
Here, we demonstrate a hybrid III-V/Silicon quantum photonic device combining
the strong second-order nonlinearity and compliance with electrical pumping of
the III-V semiconductor platform with the high maturity and CMOS compatibility
of the silicon photonic platform. Our device embeds the spontaneous parametric
down-conversion (SPDC) of photon pairs into an AlGaAs source and their
subsequent routing to a silicon-on-insulator circuitry, within an evanescent
coupling scheme managing both polarization states. This enables the on-chip
generation of broadband telecom photons by type 0 and type 2 SPDC from the
hybrid device, at room temperature and with internal pair generation rates
exceeding 105s−1 for both types, while the pump beam is strongly
rejected. Two-photon interference with 92% visibility (and up to 99% upon 5 nm
spectral filtering) proves the high energy-time entanglement quality
characterizing the produced quantum state, thereby enabling a wide range of
quantum information applications on-chip, within an hybrid architecture merging
the assets of two mature and highly complementary platforms in view of
out-of-the-lab deployment of quantum technologies