Even in the best optical fibers single photons will suffer from absorption when traveling over kilometer long distances. In order to develop the deleterious effect of such absorption we need to establish quantum repeaters which refresh the quantum information contained in transmitted photons. Essential components of such devices are quantum memories and interfaces where flying qubits, i.e. photons, are mapped onto stationary qubits, such as defect centers in diamond. Defect centers in diamond suffer from environmental noise with finite correlation time whose effect can be suppressed by dynamical decoupling techniques. In this project we are building on our work in the first generation of this collaboration and continue the development dynamical decoupling techniques and pursue their application in quantum memories in close collaboration with the group of Fedor Jelezko at Ulm.