The goal of this project is to pave the way for long-distance quantum communications between superconducting quantum (sub)processors with optical photons. We shall develop integrated chips for the conversion between microwave and optical photons using ultracold atomic ensembles. The hybrid chip developed in this project, with atoms simultaneously interacting with microwave and optical cavity fields, could be connected to superconducting quantum processors and fiber optical communication networks for realizing coherent links between distant computational nodes. Our project will demonstrate experimental techniques for microwave to optical conversion that are integrable on chips. We will fabricate planar superconducting cavities as well as integrated optical waveguides and cavities. After separate evaluation and benchmarking of the optical and microwave components in dedicated cold atom experiments, we will fabricate hybrid chips that combine both. The final goal of the project is to evaluate the operation and optimal design of a superconducting atom chip with integrated microwave and optical cavities for the coherent transduction of photons. This project combines the expertise of five groups (Tübingen - UT, Bordeaux – LP2N, Budapest – WRCP, Turin – INRIM, Heraklion - FORTH) of experimental and theoretical physics, from five european countries: Germany, France, Hungary, Italy and Greece. The project will contribute to scientific excellence, competitiveness and leadership in the broad field of Quantum technologies at European level. The project will explore several new functional units of a chip-based coherent interface between microwave and optical photons, paving the way towards the realization of quantum links between distant quantum (sub)registers implemented with SC circuits. The research has direct implications to the fields of quantum communication, quantum computation, and quantum metrology and sensing.