Integrated quantum photonics

Quantum information processing is an emerging field which promises secure communication or computational speed-ups for certain important computational problems if they are tackled with quantum computers. This has stimulated intense research on a variety of quantum bit (qubit) carriers and quantum technological platforms. Single photons are a prime qubit for the propagation and processing of quantum information, as they can be transmitted over long distances with low loss and manipulated by linear optical elements. However, the production, processing and detection of single photons is still mostly realized using bulky free-space or fiber-optic devices, posing severe challenges if more complex quantum circuits with high functionality going beyond a few photonic qubits are considered. Waveguide integrated quantum photonic circuits provide a route to overcome such limitations [1], where we target in this work the full integration of active and passive quantum devices on a single GaAs chip.