Transition dynamics in optical fiber amplifiers operating in the normal dispersion regime

Over the past decade there has been large interest in ultrafast optical fiber amplifiers operating in the normal dispersion regime because of the discovery that, high-energy pulses with a parabolic intensity profile and linear frequency chirp are the asymptotic solution to the system for arbitrary initial conditions [1]. These so-called “similariton” solutions propagate in a self-similar manner, holding certain relations (scaling) between pulse power, duration, and chirp parameter. While the asymptotic similariton features seem now well understood [1], the physics of the transition to this solution from arbitrary initial pulses has not been fully explored yet (most of the previous attempts to answer this question have focused on an initial parabolic pulse [2]). In this work, we provide a theoretical and experimental description of the adiabatic transition from an arbitrary low-energy initial condition to the asymptotic similariton state.