Future long range and efficient quantum communication links require quantum repeater nodes, in which single photons are stored and on-demand released in a so-called quantum memory. Such quantum memories rely on specific optical transitions, for instance of NV-centers in diamond or rare earth ions in crystal lattices. All these transitions are usually in the visible or near-infrared range, whereas the optimum wavelength for the transmission in a fiber network is in the telecom band around 1.55 µm. Thus, key components for such quantum repeater nodes are single photon frequency converters interfacing the quantum memory wavelength with the telecom band.
Such frequency converters can be realized exploiting three wave mixing processes (like sum frequency or difference frequency generation) in a material with X(2) optical nonlinearity. The goal of this project is to develop compact integrated optical modules. Based on our lithium niobate technology we plan to develop complex integrated optical circuits. These do not only include the nonlinear optical frequency converter in a periodically poled waveguide but also additional elements like pump couplers and appropriate waveguide circuits. The chips will be pigtailed with single mode fibers and properly packaged (see figure).
The work is embedded within a national cooperative project with several partners, which is funded by the BMBF (i.e. the Federal Ministry for Eduaction and Research). Our activities will in particular be linked to partners developing quantum memories. A close cooperation with these groups in envisaged.
Within this Ph.D. work, you will work together with other Ph.D. students and Postdocs as well with our experienced technology team. So you can benefit from our knowledge and expertise. But you will have also the freedom to work independently on your own setup.
Interested? Please get in touch with
Dr. Harald Herrmann
Phone: +49 5251 60 5879
Prof. Christine Silberhorn
Phone: +49 5251 60 5884