We demonstrate a monolithic III-V photonic circuit combining a heralded single photon source
with a beamsplitter, at room temperature and telecom wavelength. Pulsed parametric down-
conversion in an AlGaAs waveguide generates counterpropagating photons, one of which is used
to herald the injection of its twin into the beamsplitter. We use this configuration to implement an
integrated Hanbury-Brown and Twiss experiment, yielding a heralded second-order correlation
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02 that confirms single-photon operation. The demonstrated generation and
manipulation of quantum states on a single III-V semiconductor chip opens promising avenues
towards real-world applications in quantum information.