We present what is to our knowledge the first general theory for describing interacting well-separated gray spatial solitons, propagating in an arbitrary self-defocusing nonlinearity. It reveals why two dark solitons will in general repel, becoming less dark as they propagate. The results are illustrated with analytic expressions for the Kerr and the saturating nonlinearities.
© 1994 Optical Society of America
L. Lerner, D. J. Mitchell, and A. W. Snyder, "Interacting gray solitons," Opt. Lett. 19, 1302-1304 (1994)