  Collisions of left- and right-polarized spatiotemporal optical solitons have
been numerically simulated for a locally isotropic focusing Kerr medium with
anomalous chromatic dispersion. The stable propagation of such ``light
bullets'' in a moderate nonlinear regime is ensured by a transverse parabolic
profile of the refraction index in a multimode waveguide. The transverse motion
of centers of mass of wave packets in such systems occurs on classical
trajectories of a harmonic oscillator, whereas the motion in the longitudinal
direction is uniform. Therefore, collisions of two solitons can be not only
head-on but also tangential. An inelastic collision of two solitons with
opposite circular polarizations can result either in two binary light bullets
combining the left and right polarization or in more complex bound systems.
  DOI: 10.1134/S0021364024600691
