A quantum network interconnects different quantum systems via photons to allow for more advanced quantum information processing than a single system could perform on its own. A hybrid quantum network consists of nodes of different types, e.g. quantum memories, single-photon sources or trapped-ion-based quantum processors, which all carry out their dedicated tasks. In such a hybrid network, these various nodes will naturally emit and absorb photons at different wavelengths and with different spectral bandwidths.
In order to perform advanced quantum information processing, high-visibility two-photon interference between the photons from the different nodes is needed. This is only effective, however, if the spectra of the photons match in central wavelength as well as in bandwidth. It is, therefore, a key challenge for hybrid quantum networks to match the spectral properties of photons from dissimilar sources.
In this joint project together with the team of Michał Karpiński from the University of Warsaw, Poland, we develop the tools to achieve precisely this matching. In particular, we aim to demonstrate high-visibility interference between photons emitted by two very different, yet both widely used, types of photon sources: quantum dots and spontaneous parametric down-conversion. We will first match photons with initially compatible central wavelengths, but mismatched spectral bandwidths via electro-optic time-frequency shaping. We will then employ nonlinear optical time-frequency shaping methods to match photons of initially different central wavelengths and bandwidths. In addition, we will match both photons to an established telecommunication standard, which is designed for resource-efficient long-distance communication.
Our approach will be the first to allow the simultaneous matching of central wavelength and bandwidth. At the same time, the active bandwidth shaping produces much lower loss than passive filtering. These properties should be promising for the design of future quantum networks.
Researchers: Luis Matheis, Robert Keil (PI)
Funding: FWF 10.55776/PIN6357923, 2024 - 2027
