Intermodal nonlinear effects mediated optical event horizon in short-length multimode fiber
AbstractThe group-velocity-led optical event horizon (OEH) in optical fibers provides a convenient way to efficiently control a weak dispersive pulse by a comparatively strong solitonic pulse. State-of-the-art experiments demonstrating OEH make use of two different light sources, which increases the system complexity and cost. Here, we propose an elegant and cost-effective approach to observe the OEH through intermodal nonlinear interaction between azimuthally symmetric LP01 and LP02 modes of a specially designed triple-clad multimode fiber through only a single pump. The simultaneous control over dispersion and the walk off of LP01 and LP02 modes of the designed fiber pave the way for the OEH interaction. The LP02 mode possesses anomalous dispersion, while the LP01 mode exhibits normal dispersion over the wavelength range of interest. Depending upon the location of the input pump wavelength, the LP02 soliton can reflect a weak copropagating LP01 dispersive pulse, which possesses the same carrier wavelength as the soliton. The findings of this work might be useful for all-optical switching and also for the optical transistor action, where the increased feasibility is obtained by the fact that the proposed approach does not require separate input wavelengths for the soliton and the dispersive pulse. Moreover, a tunable pump source can be used to observe either a redshift or a blueshift in the dispersive pulse.