Abstract

Fundamental soliton beams have been observed in nonlinear Kerr media. Several soliton beams propagating simultaneously are coupled by the nonlinear effect. These couplings lead to high order soliton beams for superimposed input fundamental solitons or to soliton beam interactions (attraction, repulsion or energy transfer) for separate input fundamental solitons. In this paper, we report experimental observations of second and third order solitons and attraction or repulsion of two separate fundamental soliton beams. High-order solitons have been studied in a CS₂ planar waveguide having a half soliton period length. The source was a doubled frequency Nd:YAG laser followed by a pulse shaping device. A quasi-steady excitation by a plateau shaped pulse has enabled us to observe the beam narrowing of the second order soliton and the beam splitting of the third one, after half soliton period propagation. Using a bell shaped pulse excitation and a temporal analysis of the output beam by a streak camera, the half soliton period pattern evolution has been recorded for slow power scanning up to the third order soliton power. Even with such continuous power variation only pure 1st, 2nd, and 3rd soliton patterns have been observed with very fast transitions. Soliton beam interactions have been observed in an equivalent two dimensional nonlinear propagation (CS₂ cell). The source was still a doubled Nd:YAG laser but without a pulse shaping device. The laser beam passing through a Micheleon interferometer and imaging devices gives rise to two soliton beams of adjustable spacing and relative phase. Attraction and repulsion among the two beams have been observed for inphase and out of phase by π input solitons respectively. Influence of beam spacing on the interaction intensity has also been demonstrated.

© 1990 Optical Society of America