One of the grand visions of quantum information processing and communication is the implementation of a ‘quantum internet’. Amongst others, this next-generation internet will enable quantum-secure communication, quantum cloud computing, and precision measurements that benefit from remotely shared entanglement. The Joint Lab Photonic Quantum Technologies works towards this vision by developing robust, optical chip-based quantum devices that can be directly interfaced with optical fibers.
Our research combines two recent breakthroughs at the frontier of quantum optics and nanophotonics: (i) ultra-strong quantum optical nonlinearities and (ii) nanofabricated optical waveguide chips that permit high-level control of light confinement and propagation.
Our development of chip-integrated optical components (waveguides, beamsplitters, optical circulators and resonators) is based on lithographic processing of dielectric materials like silica on silicon and gallium phosphide, combined with direct write techniques using focused beams of laser light, electrons, and ions. The on-chip components that will be fabricated with these techniques then constitute the technological platform for low-loss, quantum nonlinear optical devices.
For this purpose, ultra-strong optical nonlinearities shall ultimately be co-integrated in a quantum chip. The conceptually simplest type of quantum nonlinearity arises when two photons simultaneously interact with a two-level quantum emitter that is strongly coupled to the optical mode containing the photons. To achieve strong coupling, we employ on-chip optical microresonators with high quality factor and small mode volume. Therewith, this approach aims at laying the foundations for a scalable quantum-enabled optical device technology realizing, e.g., nondestructive photon-number-resolving detectors, configurable photon-number-specific filters and sorters, or error-proof Bell-state analyzers for entangled photon states.
The Joint Lab Photonic Quantum Technologies is part of the research area Integrated Quantum Technology at FBH and is operated jointly by FBH and the Fundamental of Optics and Photonics group headed by Prof. Arno Rauschenbeutel at Humboldt-Universität zu Berlin.