Optical frequency combs are extraordinary tools for metrology which have been recently crowned by a Nobel prize: they have replaced complicated frequency chains to perform direct frequency and time measurements with much higher accuracy, which is now getting close to the quantum limit. However, quantum aspects of measurements performed with these sources have not yet been studied. This is the subject of this proposal. Based on model experiments such as space-time positioning, dispersion, velocity or frequency measurements, we propose to assess and reach experimentally ultimate limits derived from information theory in presence of quantum noise. We also propose to go beyond these limits using non-classical states. More specifically, we propose to fulfil the following objectives : " Objective 1 : achieve the best absolute space-time positioning sensitivity ever using quantum optics techniques applied to frequency combs. " Objective 2 : apply those techniques to other high sensitivity measurement such as dispersion, velocity or frequency metrology. " Objective 3 : explore fundamental quantum physics effects in the lab with quantum frequency combs. These tasks will be performed by developing a quantum frequency comb factory, based on mode locked laser sources and parametric oscillators, whose conception is a research line in itself, and that would also be used for new quantum states generation such as macroscopic entanglement and multimode states.