Quantum Technology promises tremendous advances in information processing, communication, and sensing, but current implementations do not yet integrate all essential building blocks and neither scale to large system size. Here we focus on photonic approaches, which are a frontrunner for quantum communication applications but also hold promise for optical quantum computing, simulation, and remote sensing. We identify quantum light sources, nanophotonic circuit components and single-photon detectors as essential building blocks and show how these can be replicated in large numbers on semiconductor chips by leveraging modern nanotechnology. Lithographic techniques allow for integrating solid state single-photon sources into dielectric waveguides with high yield and tailor their emission characteristics using photonic crystal cavities. We show how photons supplied into on-chip networks can be processed using nanophotonic circuit elements, for which we introduce a novel reinforcement-learning-based inverse design technique that yields high-performance devices of minimal footprint. Waveguide-integrated superconducting nanowire single-photon detectors (SNSPDs) further satisfy the need for efficient on-chip detection capabilities. We realize SNSPDs in large numbers and combine leading performance parameters with efficient fiber optic interconnects, which we exploit for high-rate quantum key distribution. Progress towards integrating sources, circuits, and detectors on silicon chips will thus allow us to study systems aspects in complex quantum networks and expand current quantum technology capabilities.
Professor Carsten Schuck works at the Center for NanoTechnology (CeNTech), the Center for Soft Nanoscience (SoN) and the Physics Institute of the University of Münster (Germany). His academic activities focus on quantum technology and nanophotonics, in particular the integration of quantum emitters and superconducting single-photon detectors with nanophotonic circuits. Before his appointment as full professor (2021), he was an as Assistant Professor in Münster (2016), after a postdoctoral fellowship at Yale University (USA) and work for ASML Research (The Netherlands). He studied physics in Hamburg, Munich, and Uppsala (Sweden) and obtained his PhD degree in Applied Physics for work with single-trapped ions at the Institute of Photonic Sciences, ICFO, in Barcelona (Spain). Prof. Schuck is the co-founder of Pixel Photonics, a start-up company that commercializes superconducting nanowire single-photon detectors.