Elastic tape behavior of a bi-directional Kerr-lens mode-locked dual-comb ring laser

We experimentally investigate a fixed point of a bi-directional dual-comb ring laser and the behavior of dual-comb signals in different spectral regions. We show that the results are quite different from those obtained with traditional dual-comb spectroscopy. We explain the difference using the elastic tape formalism that we apply to a bi-directional ring laser. We also discuss how the results can aid efforts to synchronize two bi-directional laser systems to enable rapid and high-resolution multidimensional coherent spectroscopy with a compact apparatus.