Binding mechanism of temporal soliton molecules

Temporal optical soliton molecules were recently demonstrated; they potentially allow a further increase of data rates in optical telecommunication. We present a theoretical study aimed at an explanation of the mechanism responsible for the binding force. To this end we use a perturbation treatment in several variants. We find that the well-known soliton interaction as mediated by the optical Kerr effect, when suitably modified for chirped pulses, captures essential features like the existence of a stable equilibrium separation and small-scale oscillations around this point. Predictions of these models are compared to numerical simulations.