3D integration of YSO crystal on ion-exchanged glass waveguides for optical quantum memories

Quantum communications are increasingly being developed since they ensure a private and secure transmission of data. However, their intrinsic strength, the impossibility of cloning a quantum data, entails also a major challenge that is the implementation of quantum repeaters. Based on the propagation of photon entanglement, these devices are not relying on optical amplifiers like their classic counterpart but are comparing pairs of photons thanks to quantum optical memories. Two main options are currently studied for implementing this function: the first one is using cold atoms while solid state solutions are based on erbium ions highly diluted into crystals operated at cryogenic temperatures. In this communication, we propose the integration of Er-doped Yttrium Orthosilicate, Y2SiO5 (YSO) on an ion-exchanged waveguide in order to combine the excellent quantum properties of Er-YSO with the reliability, efficiency and compactness of integrated devices on glass. We will present the design, fabrication and characterization of this hybrid waveguide as well as its qualification at low temperature.