Temporal Soliton Molecules: Experimentally determined phase profiles

We demonstrated recently both numerically and experimentally that two such signal pulses can form a stable bound state at a certain close spacing on the order of the pulse width, provided they are in antiphase. This bound state has been called a soliton molecule, and may allow denser packing of signals and thus an increase of the data-carrying capacity of fibers. As we set out to systematically characterize the range of existence and the stability properties of the soliton molecule, it became evident that the phase dynamics inside the pulse is responsible for the binding mechanism. We therefore adopted a FROG variant called VAMPIRE (very advanced method of phase and intensity retrieval of E-fields), in which the pulse to be measured is correlated with a reference pulse as in blind-FROG.