The implementation of fully integrated single-photon sources and detectors into waveguide structures such as photonic crystals or a slab and ridge waveguide is currently one of the major goals in the linear optics quantum computation and communication community. Here, we present an implementation of a single-photon on-chip experiment based on a III–V semiconductor platform. Individual semiconductor quantum dots were used as pulsed single-photon sources integrated in ridge waveguides, and the on-chip waveguide-beamsplitter operation is verified on the single-photon level by performing off-chip photon cross-correlation measurements between the two output ports of the beamsplitter. A degree of polarization of the emitted photons above 90% is observed and a careful characterization of the waveguide propagation losses in straight (< 1.5 dB mm -1) and bent (~ (8.5 ± 2.2) dB mm -1) sections documents the applicability of such GaAs-based waveguide structures in more complex photonic integrated circuits. The presented work marks an important step towards the realization of fully integrated photonic quantum circuits including on-demand single-photon emitters.
Publication: Monolithic on-chip integration of semiconductor waveguides, beamsplitters and single-photon sources
Klaus D Jöns, Ulrich Rengstl, Markus Oster, Fabian Hargart, Matthias Heldmaier, Samir Bounouar, Sven M Ulrich, Michael Jetter and Peter Michler 
J. Phys. D: Appl. Phys. 48 085101
Contact person: Dr. M. Jetter