In this project it is planned to establish an optical link between various DLR departments at different locations, as well as with the following institutions: TUM (Technische Universität München), LMU (Ludwigs-Maximilians-Universität München), MPQ (Max-Planck-Institut für Quantenphysik, Garching) and PTB. This project should make it possible to establish a stable frequency and timing connection between the aforementioned locations, and thus provide a robust and highly accurate timing system across sites. Additionally, other new technologies are to be tested, such as Quantum Key Distribution.