Experimental Observation Of Soliton Interaction Over Very Long Fiber Paths: Discovery Of A Long Range Interaction.

We have studied the interaction of ~55 ps duration soliton pulse pairs over thousands of kilometers of optical fiber with loss periodically compensated by Raman gain. We indeed observe the expected, short range, phase dependent interaction. But we also observe a long range, phase independent interaction, caused by dispersive wave radiation from the solitons.