  We propose a novel measurement technique that exploits the high coherent
controllability of multi-comb systems, which corresponds to a generalization of
the frequency control between the comb sources. In this paper, we particularly
focus on the arbitrary relative carrier envelope phase (CEP) control through
the relative offset frequency of two combs. We successfully demonstrate
polarization-modulated comb generation and its coherent detection in the
developed system. The proof-of-principle experiment indicates the potential of
multi-comb systems, enabling a rapid, precise, and arbitrary coherent
modulation method utilized for a wide variety of metrological applications.
